Appendix:Irish third-declension nouns

Monosyllabic nouns of the third declension end in a wide range of broad and slender consonants, e.g., droim m, fuil f, gleann m.

There are many polysyllabic nouns with typical third declension suffixes. Many are used to create verbal nouns, which are in the third declension when substantive, e.g., tógáil f, imirt f, cailliúint f. Others are used to create: agent nouns, e.g., bádóir m, cuiditheoir m, siúinéir m; and abstract nouns, e.g., cumhacht f, eolaíocht f.

The suffix list highlights the gender associated with each.

• -aeir, -éir m
• -óir m, -eoir
• -úir m, -iúir
• -áil,^[1] -eáil
• -aíl, -íl
• -airt, -irt f
• -áint f, -eáint
• -úint f, -iúint
• -acht f, -eacht / -aíocht, -íocht

The third declension genitive singular is characterised by ending with a broad consonant plus ‑a:

• gleann m, gleanna.

The final consonant of slender radicals is broadened:

• droim m, droma
• fuil f, fola
• tógáil f, tógála.

For the suffix ‑íl, an o is inserted to preserve broadness:

• -íl f, -íola.

For the suffix ‑úint, the final t is dropped:

• leanúint f, leanúna.

For the suffix ‑irt, the final t is lenited:

• imirt f, imeartha.

A weak plural is characterised by the genitive plural having the same form as the nominative singular. There are very few ^[2] nouns classed as such in the third declension. The genitive singular and nominative plural of all of these nouns end in ‑a.

• as m (“time”), gs. -a, npl. -a (lit.)
• béas m (“habit”), -a, -a
• crios m (“belt”), creasa, creasa (also strong)
• dath m (“colour”), -a, -a (also strong)
• deasghnáth m (“rite”), -a, -a
• dol m (“loop”), -a, -a
• dreach m (“appearance”), -a, -a (also as "front (lit.)", 2nd)
• dreas m (“duration”), -a, -a
• dún m (“fort”), -a, -a (also 1st, strong)
• fuath m (“shape”), -a, -a (also strong)
• mionn m (“oath”), -a, -aí (note plural)
• ros m (“wooded headland”), -a, -a (also as "linseed", 1st weak)
• tráth m (“period”), -a, -a (also strong)
• tréad m (“flock”), -a, -a
• treas m (“file”), -a, -a
• ur m (“border”), -a, -a (lit.)
• smacht m (“control”), -a, -a

A strong plural is characterised by the genitive plural maintaining the same form as the nominative plural. Strong plural forms found in the third declension are:

• ‑aí, ‑í
  • monosyllabic nouns (but not verbal nouns) in ‑áil: dáil f, dálaí
  • suffixes ‑éir, ‑óir, ‑úir: bádóir, bádóirí
  • suffixes ‑áint, ‑úint: leanúint, leanúintí
  • suffixes ‑acht: eolaíocht, eolaíochtaí
• ‑ta, ‑te
  • monosyllabic nouns ending with ‑n: gleann m, gleanta; bliain f, blianta; móin f, móinte
• ‑anna, ‑eanna
  • monosyllabic nouns: am m, amanna
• ‑acha
  • verbal nouns as substansive in ‑áil: tógáil f, tógálacha
  • other examples: Samhain f, Samhnacha (with syncopation)
• ‑a:
  • not to be confused with weak plural endings
  • flaith m , flatha
  • fuil f, fola
  • muir f, mara

Monosyllablic, slender consonant

Monosyllablic, -an

Suffix -óir

The majority of third declension nouns are polysyllabic, ending in the "typical suffixes" listed above, and whose gender and plural are easily predicted:

• -éir, -óir, -úir: masculine; ‑í (slender)
• -áil, -íl for verbal nouns as substantive: feminine; + acha (broadened)
• -acht, -úint -irt: feminine; ‑í (slender)

For the remaining polysyllabic, there are some patterns:

• -ain: bliain, Samhain

There is a realtively small set^[3] of monosyllabic nouns in the third declension, having a wide range of consonant endings.

There are some patterns of note:

• roots in -i(o)-
  • usually changing to -ea- in the genitive singular (more sledom in plurals)
  • mostly masculine
• ending in -th
  • mostly masculine
• ending in broad -ch(t)
  • mostly masculine
• others to be sorted
• Substantive (as opposed to verbal) nouns in ‑acht and ‑áil may be masculine or feminine, or belong to different declensions altogether.

• bior m (“spike”), beara, -anna
• bith m (“world”), beatha
• bleacht m (“milk”), -a (originally bliocht)
• briocht m (“charm”), breachta, -aí
• cion m (“love”), -a, -ta
• cith m (“shower”), ceatha, ceathanna
• crios m (“belt”), creasa, -anna (also weak form)
• fios m (“knowledge”), feasa-
• leann m (“ale”), -a, -ta (originally lionn)
• lionn m (“humour (corp.)”), leanna, -ta
• lios m (“ring-fort”), leasa, -anna
• liost m (“teasal”), -a, -anna
• mil f (“honey”), meala
• riocht m (“shape”), -a, -aí
• sioc f (“ice”), seaca
• siorc m (“shark”), -a, -anna (gs not with -ea-)
• sliocht m (“track”), sleachta, sleachta (strong plural)
• slios m (“side”), sleasa, sleasa (strong plural)

• áth m (“ford”), -a, -anna
• bláth m (“flower”), -a, -anna
• both f (“hut”), -a, -anna
• bruth m (“heat”), -a, -anna
• cath m (“battle”), -a, -anna
• cruth m (“shape”), -a, -anna
• dath m (“colour”), -a, -anna
• fáth m (“cause”), -a, -anna
• guth m (“voice”), -a, -anna
• rath m (“favour”), -a
• ráth m (“fort”), -a, -anna (as f, "shoal"; as weak, "guarantor")
• scáth m (“shadow”), -a, -anna
• scoth m (“flower”), -a, -anna
• snáth m (“thread”), -a
• sruth m (“stream”), -a, -anna
• tráth m (“period”), -a, -anna (weak version also)

• acht m (“act; doubt”), -a, -anna
• beacht m (“exact measure”), -a
• brach m (“pus”), -a
• ceacht m (“lesson”), -a, -anna
• créacht f (“wound”), -a, -aí
• deacht m (“dictum”), -a, -anna
• dleacht f (“due”), -a, -anna
• dreach m (“appearance”), -a, -a (weak)
• dréacht m (“draft”), -a, -aí
• éacht m (“slaughter”), -a, -aí
• feacht m (“current”), -a, -aí
• fuacht m (“cold”), -a
• leacht m (“grave”), -a, -anna
• léacht f (“lecture”), -a, -aí
• loch m (“lake”), -a, -anna
• locht m (“fault”), -a, -anna
• luach m (“value”), -a, -anna
• lucht m (“charge”), -a, -anna
• neacht f (“niece”), -a, -anna
• ócht f (“virginity”), -a
• reacht m (“law”), -a, -anna
• slacht m (“neatness”), -a
• smacht m (“control”), -a, -a (weak plural)
• trácht m (“traffic”), -a

• ab m (“abbot”), -a, -aí
• am m (“time”), -a, -anna
• aos m (“people”), -a
• béas m (“habit”), -a, -a (weak)
• cac m (“shit”), -a, -anna
• Cáisc f (“Easter”), Cásca
• cead m (“permission”), -a, -anna
• cíos m (“rent”), -a, -anna
• cleas m (“trick”), -a, -anna (also 1st)
• cnámh m (“bone”), -a, -a (also 2nd)
• cóir f (“justice”), córa, córacha
• corcair m (“purple dye”), corcra
• creamh m (“wild garlic”), -a
• cuid f (“part”), coda, codanna
• dáil m (“meeting”), dála, dálaí
• dair f (“oak”), dara, daracha (also 5th)
• deoin f (“consent”), deona, deonta
• dream m (“tribe”), -a, -anna
• droim m, droma, dromanna
• dún m (“fort”), -a, -a (weak; also 1st, strong)
• eang f (“track”), -a, -aí
• eas m (“waterfall”), -a, -anna (as weak "stoat")
• feadh m (“extent”), -a
• feag f (“rush”), -a, -acha
• feoil f (“meat”), feola, feolta
• fíon m (“wine”), -a, -ta
• flaith m (“prince”), flatha, flatha
• fuath m (“shape”), -a, -a (weak and strong forms)
• fuil f (“blood”), fola, fola
• gean m (“love”), -a
• gleann m (“valley”), -a, -ta
• greim m (“grip”), greama, greamanna
• leas m (“benefit”), -a
• lus m (“herb”), -a, -anna
• meas m (“opinion”), -a
• meath m (“decay”), -a
• modh m (“manner”), -a, -anna
• móin f (“turf”), móna, -te
• muir f (“sea”), mara, mara
• nóin f (“noon”), nóna, nónta
• rámh m (“oar”), -a, -aí (also 4th as rámha)
• rang m (“class”), -a, -anna
• ros m (“wooded headland”), -a, -a (weak)
• rud m (“thing”), -a, -aí
• scread f (“scream”), -a, -anna
• snag m (“gasp”), -a, -anna
• snas m (“polish”), -a, -anna
• sos m (“rest”), -a, -anna
• srón f (“nose”), -a, -anna (also 2nd)
• táin f (“plunder”), tána, -te
• taom m (“paroxysm”), -a, -anna (variant: tom)
• tart m (“thirst”), -a
• teas m (“heat”), -a
• toil f (“wish”), tola
• tóin f (“arse”), tóna, -eanna
• tost m (“silence”), -a, -anna
• troid f (“fight”), troda, -eanna
• úr m (“heath”), -a (as "fresh" in 1st)

For a list of nouns having third and other declension forms, see the multiple declension table in the Irish nouns appendix.

• {{ga-decl-f3}}
• {{ga-decl-f3-nopl}}
• {{ga-decl-m3}}
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• An Caighdeán Oifigiúil, 2017
• A Grammar of the Irish Language, O'Donavan, 1845
• Irish declension on Wikipedia
• Irish declension on WikiBooks, with exercises
• Declension overview and guesser on Nualéargais
• Irish declension overview on Project Gutenberg

• Wiktionary:About Irish

• Category:Irish language
  • Category:Irish third-declension nouns

• Appendix:Irish nouns
  • Appendix:Irish first-declension nouns
  • Appendix:Irish second-declension nouns
  • Appendix:Irish fourth-declension nouns
  • Appendix:Irish fifth-declension nouns