The phrase "smack into" is often used to describe a forceful collision or impact between two objects. However, there are several synonyms that can be used to convey a similar meaning. "Crash into" and "collide with" are two commonly used options, while "slam into" and "ram into" emphasize a more forceful impact. "Bang into" and "bump into" are more casual and informal synonyms. "Plow into" is another option, often used to describe a collision with significant force. Whatever the synonym used, it conveys a sense of sudden impact and forceful collision.