From Longman Dictionary of Contemporary Englishsmash something ↔ down phrasal verbHIT/BUMP INTOto hit a door, wall etc violently so that it falls to the ground → smash→ See Verb table
Examples from the Corpus
smash down• I just wanted to go out and smash a door down.• He just smashed the bottle down across my hand.• They used to smash it down, and it inevitably wound up spilling all over the car.• Yardies called by, smashed his door down, grabbed the man, threw him out through that eighth floor window. 