Rouse gentleman -- about time (4)
I believe the answer is:
stir
'rouse' is the definition.
(thesaurus)
'gentleman about time' is the wordplay.
'gentleman' becomes 'sir' (I've seen this before).
'about' means one lot of letters goes inside another.
'time' becomes 't'.
'sir' placed around 't' is 'STIR'.
(Other definitions for stir that I've seen before include "Disturb" , "unrest" , "Arouse (a memory)" , "jail" , "cooler" .)