Editing Openai/69186d20-2d14-8013-b9c6-c09000f173f6 (section)

==== This is the one you actually feel in everyday syntax. ====

===== - Possession / “of”: - carr an fhir “the man’s car” - doras an tí “the door of the house” =====
* Noun–noun compounds (kind-of / type-of): - múinteoir Gaeilge “Irish teacher” (teacher of Irish) - leabhar gramadaí “grammar book”
* After certain prepositions: historically dative/genitive interactions; in the standard you mostly treat them as governed forms: - os comhair an tí “in front of the house” (genitive after os comhair)

===== - Masculine: often no article lenition, but genitive form changes: - fear → fir - bád → báid (many add/slenderize final) =====
* Feminine: often lenition in the genitive with article na: - bean → na mná - an chathair “the city” → lár na cathrach “the middle of the city”

You can think of “learn the genitive singular as a lexical property” for common nouns; the rules are messy but patterns emerge with practice.