Mean to cover up leg this evening (7)
I believe the answer is:
tonight
'this evening' is the definition.
(synonyms)
'mean to cover up leg' is the wordplay.
'mean' becomes 'tight' (both can mean miserly).
'to cover up' indicates putting letters inside.
'leg' becomes 'on' (cricket term, fielding positions).
'tight' going around 'on' is 'TONIGHT'.
(Other definitions for tonight that I've seen before include "West Side Story number" , "late in the day" , "after supper?" , "the coming time for retirement" , "Selection from West Side Story" .)