Prescribe line, for example, given one’s behind time (9)
I believe the answer is:
legislate
'prescribe' is the definition.
(thesaurus)
'line for example given one's behind time' is the wordplay.
'line' becomes 'l'.
'for example' becomes 'eg' (synonyms).
'given' is a charade indicator (letters next to each other).
'one's' becomes 'is' (roman numeral).
'behind time' becomes 'late' (I've seen this before).
'l'+'eg'+'is'+'late'='LEGISLATE'
(Other definitions for legislate that I've seen before include "Make or enact laws" , "what parliament must do" , "Pass laws" , "put in force" , "what members do?" .)