The term 'enter forcefully' can be summarized by two crossword solutions: INVADE (6 letters) and BUSTINTO (8 letters). To INVADE is to enter a place with military force, often with the intention of conquering or occupying it. Bustinto is a more general term that means to enter a place forcefully, often without permission. Both terms imply a forceful entry, but the difference is that invading implies a military action while bustinto does not.