Drive time's up unfortunately (7)
I believe the answer is:
impetus
'drive' is the definition.
(impetus is a drive to do something)
'time's up unfortunately' is the wordplay.
'unfortunately' is an anagram indicator (a bad or unfortunate spelling).
'times'+'up'='timesup'
'timesup' is an anagram of 'IMPETUS'.
(Other definitions for impetus that I've seen before include "Driving force, momentum" , "Motivation" , "Incentive - time's up (anag)" , "influence" , "Momentum, stimulus" .)