impregnate vs knock up

impregnate and knock up both are verbs.

Word	Noun	Adjective	Verb	Adverb
impregnate	No	No	Yes	No
knock up	No	No	Yes	No

As verbs, impregnate and knock up are synonyms defined as:

Other synonyms of impregnate include bang up, prang up.

impregnate (verb)	knock up (verb)
make pregnant	make pregnant
fertilize and cause to grow
infuse or fill completely
fill, as with a certain quality