Time off I certainly required after case of lice! (7)
I believe the answer is:
leisure
'time off' is the definition.
(time off work)
'i certainly required after case of lice' is the wordplay.
'certainly' becomes 'sure' (synonyms).
'required' says to put letters next to each other.
'after' is a charade indicator (letters next to each other).
'case of' means to remove the middle letters (outsides of).
'lice' with its centre removed is 'le'.
'i' put next to 'sure' is 'isure'.
'isure' put after 'le' is 'LEISURE'.
(Other definitions for leisure that I've seen before include "Enjoyment of free time" , "Breathing space" , "Freedom from work" , "Free time; relaxation" , "R&R" .)