1 PHRASAL VERB 草草做成（或建成）；匆匆拼凑成 If you knock something up, you make it or build it very quickly, using whatever materials are available. 草草做成（或建成）；匆匆拼凑成 [informal] [Also VERB n PREPOSITION]
2 PHRASAL VERB 敲门唤醒 If you knock someone up, you knock on the door of their bedroom or of their house in the night or in the morning in order to wake them up. 敲门唤醒 [British, informal] [Also VERB PREPOSITION n (not pron)]
SYN wake up, wake, get up, revive
3 PHRASAL VERB [usually passive] 使怀孕 If a woman is knocked up by a man, she is made pregnant by him. 使怀孕 [mainly US, informal, rude]