Endeavour to go in by force (10)
I believe the answer is:
enterprise
'endeavour' is the definition.
('enterprise' can be a synonym of 'endeavour')
'go in by force' is the wordplay.
'go in' becomes 'enter' ('enter' can be a synonym of 'go in').
'by' is a charade indicator (letters next to each other).
'force' becomes 'prise' (I've seen this before**).
'enter'+'prise'='ENTERPRISE'
'to' acts as a link.
(Other definitions for enterprise that I've seen before include "drug business" , "Bold resourcefulness" , "Project, undertaking" , "Get-up-and-go - venture" , "New project" .)