Synonyms: sink, slide down, slump
Definition: fall or sink heavily
Usage: He slumped onto the couch; My spirits sank
Similar words: founder, fall in, break, cave in, collapse, give, give way
Definition: break down, literally or metaphorically
Usage: The wall collapsed; The business collapsed; The dam broke; The roof collapsed; The wall gave in; The roof finally gave under the weight of the ice