Verify clubs working with company (7)
I believe the answer is:
confirm
'verify' is the definition.
(I've seen this before)
'clubs working with company' is the wordplay.
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'working' becomes 'on' (on can mean working or activated).
'with' means one lot of letters go next to another.
'company' becomes 'firm' (I've seen this before).
'c'+'on'+'firm'='CONFIRM'
(Other definitions for confirm that I've seen before include "Make (provisional arrangement) definite" , "Provide support for the truth" , "Substantiate" , "Philosophy of life" , "Bishop may" .)