A company on leave (7)
I believe the answer is:
abandon
'leave' is the definition.
(to abandon is to leave or desert)
'a company on' is the wordplay.
'company' becomes 'band' (I've seen this before).
'a'+'band'+'on'='ABANDON'
(Other definitions for abandon that I've seen before include "Give up (something) completely" , "Desert; intemperance" , "Stop" , "Leave behind - licentiousness" , "Lack of constraint" .)