Genitive Case

Use of the Genetive Form

The genitive case, in general, is used to take Noun A and use it to describe, define, limit, or modify Noun B. The genitive case is a signal that Noun A is related to Noun B in a close and intimate way: in English we express the relation in terms of possession, origin, material, belonging and membership, and the like.

madra an bhuachalla – the boy’s dog.

bosca adhmaid – a wooden box (a box of wood)

Teachta Dála – representative of the Dáil

báidín Fheilimidh — Feilimidh’s little boat.

An indefinite noun in the genitive can also be used like an adjective, to describe a noun:

seomra folctha — room of washing (bathroom)

laoch cogaidh — war hero

dochtúir mná — a female doctor (a woman doctor)

In Irish, the genitive has two other major uses:

1.) It marks the direct of object of verbal nouns when they are used with “tá.”

Tá na mná ag déanamh na hoibre – the women are doing the work (the women are at the doing of the work

Bhí mé ag scríobh litreach – I was writing a letter (I was at the writing of a letter)

2.) It links a noun with a “compound preposition.” A compound preposition is a “simple preposition” (ag, i, le, etc.) and a noun, that forms a new idea, and is linked to the noun it modifies by the genitive case:

in aghaidh na naimhde — against the enemies (in the face of the enemies)

os cionn na gcrann — above the trees (over the head of the trees).

How the Genetive is Formed

In Irish, the basic form of a noun is called the nominative. The nominative singular is the form you look us in the dictionary. There are five main ways to form the genitive singular from the nominative singular, and these are the five “declensions.” (any good dictionary should tell you how to do it):

First Declension:These are generally masculine nouns that end in a broad consonant. The genitive singular is formed by making that final consonant slender, usually by adding an “i” just before it. This may cause the vowels to change:

bád -> báid
leabhar -> leabhair
fear -> fir
mac -> mic
iasc -> éisc

Most nouns that end in -(e)ach take the ending -(a)igh:

Éireannach -> Éireannaigh

Second Declension: these are mostly feminine nouns that end in either a broad or slender consonant. The genitive singular is formed by adding an “e” to the end of the nominative. If the nominative ends in a broad consonant, that consonant must be made slender by adding an “i” before it, and this may change the vowels like in the first declension:

fuinneog -> fuinneoige
muc -> muice
long -> loinge
scian -> scéine
eaglais -> eaglaise

Feminine nouns ending in -(e)ach become -(a)í:

báisteach -> báistí

Third Declension: These are both masculine and feminine, and their nominatives end in either broad or slender consonant. The genitive singular is formed by adding an “a” to the end of the nominative. If the ending is originally slender, it becomes broad:

rud -> ruda
múinteoir -> múinteora

Fourth Declension: The genitive singular is identical to the nominative singular, and you can only tell the case by the context:

an cailín -> ainm an chailín
Garda -> carr Garda mhóir

Fifth Declension: These are mostly feminine nouns, and they follow one of two patterns: they either end in a vowel and form the genitive singular by adding a consonant, or they end in -ir, -il, -in, and form the genitive by adding a broad “-ach.”

comharsa -> comharsan
cathair -> cathrach
cara -> carad

There are also a handful of irregulars that don’t fit in any declension.