a forceful person expresses their opinions very strongly and clearly and people are easily persuaded by them [= strong]
a forceful personality/character/opponent etc
He gained a reputation as a forceful member of the party.
forceful arguments, reasons etc are strongly and clearly expressed [= powerful]:
a forceful attack on government policy
having a powerful effect that is likely to change a situation:
The President hasn't been forceful enough in changing the judicial system.
Governments should adopt a more forceful approach to improve the environment.
using physical force
—forcefulness noun [uncountable]