Cooperate to act and dance (4,4)
I believe the answer is:
play ball
'cooperate' is the definition.
(thesaurus)
'act and dance' is the wordplay.
'act' becomes 'play' (play is a kind of act**).
'and' says to put letters next to each other.
'dance' becomes 'ball' (ball is a kind of dance).
'play'+'ball'='PLAY BALL'
'to' is the link.
(Other definitions for play ball that I've seen before include "Agree to comply with someone else's rules" , "Be cooperative" , "Do what is needed" , "Most boys love to" , "meet a delivery?" .)