Labour dawdle assuming a victory (7)
I believe the answer is:
travail
'labour' is the definition.
(travail is a kind of labour)
'dawdle assuming a victory' is the wordplay.
'dawdle' becomes 'trail' (trailing is a kind of dawdling).
'assuming' indicates putting letters inside.
'victory' becomes 'v'.
'a'+'v'='av'
'trail' going around 'av' is 'TRAVAIL'.
(Other definitions for travail that I've seen before include "Toil - anguish" , "Exertion, elbow grease" , "Hard work" , "Use of physical or mental energy; excessive labour..." , "Hard labour" .)