There are several synonyms for the phrase "smashing into". One of the most commonly used is the word "colliding", which refers to the impact of two objects or individuals. Another useful synonym is "ramming", which indicates a forceful impact with the intention of causing damage or destruction. Alternatively, you could use the phrase "crashing into", which implies a sudden, unexpected impact. "Slamming into" is also a good option when you want to emphasize the intensity of the collision. Other possible synonyms include "bumping into", "hitting", "striking", and "smacking into". All of these words are useful for describing the impact of one object or person against another.