Family help couple to chase gold (2,4)
I believe the answer is:
au pair
'family help' is the definition.
(I've seen this before)
'couple to chase gold' is the wordplay.
'couple' becomes 'pair' ('pair' can be a synonym of 'couple').
'to chase' says to put letters next to each other.
'gold' becomes 'au' (Au is the chemical symbol for gold).
'pair' after 'au' is 'AU PAIR'.
(Other definitions for au pair that I've seen before include "Foreign home helper" , "Young foreign person doing housework for keep" , "Family help" , "Young foreign student" , "Working lodger" .)