contract out vs sign up

contract out and sign up both are verbs.

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

As verbs, sign up is a hypernym of contract out; that is, sign up is a word with a broader meaning than contract out:

Other hypernyms of contract out include contract, sign, sign on.

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