sign up vs contract out

sign up and contract out both are verbs.

Word	Noun	Adjective	Verb	Adverb
sign up	No	No	Yes	No
contract out	No	No	Yes	No

As verbs, contract out is a hyponym of sign up; that is, contract out is a word with a more specific, narrower meaning than sign up:

sign up (verb)	contract out (verb)
join a club, an activity, etc. with the intention to join or participate	refuse to pay a levy to a union for political use
engage by written agreement	assign a job to someone outside one's own business