godan ~す verb / transitive:

• to destroy; to demolish; to pull down; to tear down; to level
• to disturb; to put into disorder; to throw off balance; to make shaky
• to relax (one's pose); to make oneself at ease
• to break (a bill); to change; to make change - oft. 札を崩す, etc.
• to write in cursive style; to write in running style - oft. as 字を崩す
• to break into a smile; to let off a smile - as 顔を崩す, etc.
• to lower (a price)