Perform in between activities (5)
I believe the answer is:
enact
'perform' is the definition.
(thesaurus)
'in between activities' is the wordplay.
'in' indicates a hidden word.
'ENACT' can be found hidden inside 'between activities'.
(Other definitions for enact that I've seen before include "Establish by law - perform" , "Pass into law" , "Ordain" , "Make (a bill) law" , "Put into practice" .)