sign vs contract

sign and contract both are nouns.

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

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

Other hypernyms of sign include undertake.

As verbs, sign and contract are synonyms defined as:

Other synonyms of sign include sign on, sign up.

sign (noun)	contract (noun)
structure displaying a board on which advertisements can be posted	a variety of bridge in which the bidder receives points toward game only for the number of tricks he bid
a public display of a message	a binding agreement between two or more persons that is enforceable by law
a gesture that is part of a sign language	(contract bridge) the highest bid becomes the contract setting the number of tricks that the bidder must make
any nonverbal action or gesture that encodes a message
a character indicating a relation between quantities
a perceptible indication of something not immediately apparent (as a visible clue that something has happened)
a fundamental linguistic unit linking a signifier to that which is signified
an event that is experienced as indicating important things to come
(astrology) one of 12 equal areas into which the zodiac is divided
having an indicated pole (as the distinction between positive and negative electric charges)
(medicine) any objective evidence of the presence of a disorder or disease

sign (adjective)	contract (adjective)
used of the language of the deaf

sign (verb)	contract (verb)
be engaged by a written agreement	be stricken by an illness, fall victim to an illness
communicate silently and non-verbally by signals or signs	make or become more narrow or restricted
mark with one's signature; write one's name (on)	become smaller or draw together
make the sign of the cross over someone in order to call on God for protection; consecrate	reduce in scope while retaining essential elements
communicate in sign language	compress or concentrate
place signs, as along a road	enter into a contractual arrangement
approve and express assent, responsibility, or obligation	make smaller
engage by written agreement	squeeze or press together
	engage by written agreement