knock up vs fertilize

knock up and fertilize both are verbs.

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

As verbs, fertilize is a hypernym of knock up; that is, fertilize is a word with a broader meaning than knock up:

Other hypernyms of knock up include fecundate, fertilise, inseminate.

knock up (verb)	fertilize (verb)
make pregnant	introduce semen into (a female)
	provide with fertilizers or add nutrients to
	make fertile or productive