Raced around first man returning fast time (7)
I believe the answer is:
ramadan
'fast time' is the definition.
(I've seen this before)
'raced around first man returning' is the wordplay.
'raced' becomes 'ran' ('run' can be a synonym of 'race').
'around' is an insertion indicator.
'first man' becomes 'adam' (I've seen this before).
'returning' says the letters should be written in reverse.
'adam' back-to-front is 'mada'.
'ran' enclosing 'mada' is 'RAMADAN'.
(Other definitions for ramadan that I've seen before include "Islam holy month" , "Muslim holy month" , "Ninth month of Muslim year, time to fast" , "Islamic fast" , "Month of fasting from dawn to dusk" .)