• (of a structure) suddenly fall down or give way

Synonyms: cave in, fall in, subside, fall down, sag, slump, settle, give, give way, crumble, crumple, disintegrate, fall to pieces, come apart

• (of a person) fall down and become unconscious as a result of illness or injury

Synonyms: faint, pass out, black out, lose consciousness, fall unconscious, keel over

• fail suddenly and completely

Synonyms: break down, fail, fall through, fold, founder, fall flat, miscarry, go wrong, come to nothing, come to grief, be frustrated, be unsuccessful, not succeed, disintegrate

• fold or be foldable into a small space

• an instance of a structure falling down or giving way

Synonyms: cave-in, giving way, subsidence, crumbling, disintegration