Father meets Irish couple (4)
I believe the answer is:
pair
'couple' is the definition.
('pair' can be a synonym of 'couple')
'father meets irish' is the wordplay.
'father' becomes 'pa' (pa is a kind of father).
'meets' is a charade indicator (letters next to each other).
'irish' becomes 'ir' (abbreviation).
'pa'+'ir'='PAIR'
(Other definitions for pair that I've seen before include "Set of two" , "Put together - two of a kind" , "item" , "Duo" , "Twosome" .)