Caibidil a Trí: The verb (an Briathar)

On the other hand, the Irish verbal noun has also verbal qualities: it can carry an adverb, have direct (accusative) objects etc.
To sum up, one can say that the German infinitive has, like the Irish verbal noun, both substantive and verbal qualities. Both come somewhere between noun and verb form, the Irish verbal noun is closer to the noun, the German infinitive is rather seen as a verb form.

Synonyms:

action word, verbal noun
Abbreviation used occasionally in this text: VN

formation:

verbs of the 1st conjugation
regular formation:

• verbal noun suffix -adh or. -eadh
  e.g. bris - briseadh (break), mol - moladh (praise)
  Often the verb root is depalatalised
  e.g. buail - bualadh (hit)
• verbs ending in -áil: verbal noun with the same ending -áil:
  e.g.: péinteáil (verb = paint) - péinteáil (verbal noun "to paint")
• verbs ending in a short vowel/consonant + -igh: verbal noun ending in -í
  (earlier -ighe, -idhe, latter, since many of these verbs ended earlier in -idh )
  e.g.: suigh - suí (sit), nigh - ní (wash)
• verbs ending in a long vowel (á, é, í, ó, ú) + -igh: verbal noun ending in -á, -é, -í, -ó, -ú
  (e.g. -ó earlier -óghadh, d.h. -ógh + -adh)
  e.g.: dóigh - dó (burn)

• suffixless (same form as the verb stem)
  e.g. ól - ól (drink)
• suffixless + depalatalisation of the verb stem
  e.g. coisc - cosc (prevent)
• verbal noun ending -amh
  e.g. déan - déanamh (make), seas - seasamh (stand), léigh - léamh (read)
• further verbal noun endings: -achtáil, -úint, -an, -int, -t, -im, -e, -áil, -ach, -acht, -achán, -áil, -aidh, etc.

verbs of the 2nd conjugation
regular formation:

• verbal noun ending: -ú
  (earlier: -ughadh, also -igh > -ugh + -adh)
  e.g. saothraigh - saothrú (work hard)
• verbs ending in a slender -l, -n, -r: verbal noun ending -t
  e.g.: oscail - oscailt (open), imir - imirt (play)

further typcal ("irregular") formations

• verbal noun ending: -í
  e.g.: éirigh -éirí (rise), cónaigh - cónaí (live)
• suffixless (same form like the verb stem or minus -igh)
  e.g.: aithris - aithris (imitate), foghlaim - foghlaim (learn), damhsaigh - damhsa (dance)
• suffixless + depalatalisation of the verb stem
  e.g.: ceangail - ceangal (connect)
• further verbal noun endings: -ach, -acht, -achtáil, -achan, -eál, -áil, -int, etc.

verbal noun without a corresponding verb

e.g. from classes of people (mostly professions)
Verbal nouns can also be formed out of types of people (mostly professions), althought there is no real corresponding verb to it. These verbal nouns are most often used in the progressive

• -acht /-eacht
  e.g.:
  feirmeoir = farmer; Tá sé ag feirmeoireacht = He runs a farm. ("is he at farmer-being")
  siopadóir = shopkeeper; Tá sé ag siopadóireacht = He runs a shop. ("is he at shopowner-being")
  cabaire = chatterbox; Tá sé ag cabaireacht = He's chattering ("is he at chatterbox-being")

formation of the genitive of the verbal noun:

the verbal adjective as the genitive form

Although they are nouns, they form their genitive often using the verbal adjective [ 1 ]:

• if they appear in "infinitive" use
  and especially then when they have a further genitive object or a possessive pronoun as an object.
  bualadh (hit):  chun a mbuailte = in order to hit her
  foghlaim (learn):  lucht foghlamtha na Gaeilge = Irish learners (lit." people of the learning of Irish ")
  ól (drink):  lucht ólta fuisce = whiskes drinkers ("people of the drinking of whiskey ")
• to form the participle with the prefix so-, do-, in- (see verbal adjective):
  briseadh (break): sobhriste = fragile
• the"regular" verbal noun ending in -adh and -ú (as well as: -á, -é, -í, -ó) always have
  a genitive in the form of the verbal adjective (in infinitive and substantivised use)
  e.g: glanadh - glanta (cleaning - of the cleaning), saothrú - saothraithe (hard work - of the hard work), suí - suite (sitting - of the sitting)

substantivised genitive

genitives, depending on the noun declension, form these (except verbal noun ending in -adh and - long vowel), if they:

• appear in "substantivised" or "infinitive"use (if they have no object ).
  e.g.: bréith (bear): lá bréithe = birthday ("day of bearing ")
  e.g.: ól (drink):  lucht óil = drinkers ("people of the drinking "),
  e.g.: foghlaim (learn):  lucht foghlama = learners ("people of the learning ")
• the verbs ending in -áil with a verbal noun ending in -áil use always
  a substanivised genitive (-ála) and never the verbal adjective as the genitive, even not in the above mentioned cases.
  Just as the many VNs ending in -áint (-ána), -úint (-úna), -cht (-chta)

substantivised genitive = verbal adjective

• verbs of the 2nd conjugation ending in -l,-n,-r with a verbal noun ending in -t the form of the genitives is always either:
  -te (form of the verbal adjective = form of the substantivised genitive, 2nd declension)
  e.g.: oscailt - oscailte (open) or:
  -tha (form of the verbal adjective = form of the substantivised genitive, 3rd declension)
  e.g.: imirt - imeartha (play)
  In these cases (by coincidence) the verbal adjective and the substantivised genitive match.

formation of the plural of the verbal nouns:

A formation of the plural is only possible in substantivised use of the verbal noun.
Many verbal nouns form the plural according to their declension.
The "regular" verbal noun ending in -adh and -ú form the plural as such

verbal noun ending in -adh:
plural by affixing an -í on the verbal adjective:
e.g.: glan (to clean):  glanadh - glanta - glantaí

verbal noun ending in -ú (or long vowels)
plural ending -uithe or -ithe
e.g.: saothraigh (to work hard): saothrú - saothruithe
(not to be confused with saothraithe, which is the verbal adjective and genitive singular of the verbal nouns)

use of the verbal nouns:

see under Syntax of the verbal noun

[ 1 ]: Why is it that the verbal adjective is the genitive of the verbal noun?:
A normal noun in the genitive is mostly an attribute (e.g. "Seáin" in "teach Sheáin = Seán's house ") and is used just like an adjectival attribute (e.g. "álainn" in "teach álainn = a beautiful house ").
The substantivised genitive acts then as quasi the "attributive form" of the noun.
The verbal adjective acts normally as the "attributive form" of the verb (e.g. "tógtha" in "teach tógtha = built house ").
If the verbal noun now is in "infinitive" use ( in stress of its verbal qualities) as an attribute (and must be set in the genitive), one reaches for the already existant attributive form of the same verb (to the verbal adjective).