kick off vs start up

kick off and start up both are verbs.

Word	Noun	Adjective	Verb	Adverb
kick off	No	No	Yes	No
start up	No	No	Yes	No

As verbs, start up is a hypernym of kick off; that is, start up is a word with a broader meaning than kick off:

Other hypernyms of kick off include commence, embark on, start.

kick off (verb)	start up (verb)
commence officially	get off the ground
	get going or set in motion