Father brought back expert quickly (5)
I believe the answer is:
apace
'quickly' is the definition.
(I know that quickly can be written as apace)
'father brought back expert' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'brought back' is a reversal indicator.
'expert' becomes 'ace' (ace can informally mean very good).
'pa' written backwards gives 'ap'.
'ap'+'ace'='APACE'
(Other definitions for apace that I've seen before include "Swiftly, quickly" , "at high speed" , "(Move on) swiftly" , "fast" , "What's quickly" .)