1 to kowtow (traditional greeting, esp. to a superior, involving kneeling and pressing one's forehead to the ground)

1 (coll.) to fight to the death

1 to tap

2 to knock (against sth hard)

3 to knock (mud from boots, ashes from a pipe etc)

1 to knock against

2 to bump into

3 to have a disagreement

4 to clash

1 bumpy (of a road)

2 limping (of a person)

1 lit. to kowtow like grinding garlic (idiom)

2 fig. to pound the ground with one's head