Manage company gym (4)
I believe the answer is:
cope
'manage' is the definition.
(manage can mean to cope or do well)
'company gym' is the wordplay.
'company' becomes 'co' (abbreviation).
'gym' becomes 'pe' (short for Physical Education).
'co'+'pe'='COPE'
(Other definitions for cope that I've seen before include "Join" , "Long cloak for a priest" , "Rise to the occasion" , "Manage effectively" , "special cloak" .)