Husband taking long time over race (4)
I believe the answer is:
hare
'race' is the definition.
(hare can mean to run fast)
'husband taking long time over' is the wordplay.
'husband' becomes 'h' (abbreviation).
'taking' is a charade indicator (letters next to each other).
'long time' becomes 'era' (a long period of time).
'over' says the letters should be written in reverse.
'era' backwards is 'are'.
'h'+'are'='HARE'
(Other definitions for hare that I've seen before include "'You can't run with the . . . . and hunt with the hounds'" , "Swift mammal" , "'Swift, long-eared animal (4)'" , "Game, -- and hounds" , "Swift rodent" .)