Father with one close pal (6)
I believe the answer is:
friend
'pal' is the definition.
(I've seen this before)
'father with one close' is the wordplay.
'father' becomes 'fr' (abbreviation as in a priest's title).
'with' says to put letters next to each other.
'one' becomes 'I' (Roman numeral).
'close' becomes 'end' (close can mean to end or finish).
'fr'+'i'+'end'='FRIEND'
(Other definitions for friend that I've seen before include "One who gives proof of genuine regard" , "Pal, amigo" , "Pal or buddy" , "Person regarded with trust and affection" , "Close or intimate acquaintance" .)