complete
fundamental, major, radical, serious

have

rethink of
to have a fundamental rethink of policy

fundamentally, radically, seriously
completely
constantly

force sb to, make sb
have to, need to
I think we may have to rethink our policies fairly radically.

begin to, start to

Rethink is used with these nouns as the object:
approach, decision, plan, priority, strategy, tactic, view