Advantage of busy worker possessing new suit (7)
I believe the answer is:
benefit
'advantage' is the definition.
(thesaurus)
'busy worker possessing new suit' is the wordplay.
'busy worker' becomes 'bee'.
'possessing' indicates putting letters inside.
'new' becomes 'n'.
'suit' becomes 'fit' ('fit' can be a synonym of 'suit').
'bee' placed around 'n' is 'bene'.
'bene'+'fit'='BENEFIT'
'of' is the link.
(Other definitions for benefit that I've seen before include "(Gain) advantage" , "Payment" , "Charity event" , "Financial assistance" , "Handout" .)