| hole(noun, nature, place, flat, retreat) |
| cavern(noun, nature, retreat, dip, hole) |
| den(noun, nature, cover, flat, house) |
| hollow(noun, adjective, area, empty, hole) |
| burrow(noun, nature) |
| grotto(noun, hole, hollow, grave, room) |
| submit(verb, break, drop, go, fail) |
| lair(noun, abode, habitat, hideout) |
| cove(noun, nature, receptacle, concavity, inlet) |
| collapse(verb, break, drop, go, open) |
| bend(noun, verb, break, drop, go) |
| cavity(noun, hole, hollow, gap, cavern) |
| bow(verb, break, drop, go, fail) |
| defer(verb, break, drop, go, fail) |
| succumb(verb, break, drop, go, fail) |
| tunnel(noun, nature) |
| undermine |
| buckle(verb, break, drop, fail, agree) |
| give way(verb, expression, phrasal verb, break, drop) |
| give(verb, break, drop, go, fail) |