contract has 23 distinct synonyms spread across 10 of its 12 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is expand.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
engage by written agreement
“They signed two new pitchers for the next season”
compress or concentrate
“Congress condensed the three-year plan into a six-month plan”
make or become more narrow or restricted
“The selection was narrowed”
reduce in scope while retaining essential elements
“The manuscript must be shortened”
a binding agreement between two or more persons that is enforceable by law
(contract bridge) the highest bid becomes the contract setting the number of tricks that the bidder must make
a variety of bridge in which the bidder receives points toward game only for the number of tricks he bid
Synonyms, antonyms and the broader and narrower relations for contract come from Princeton University’s WordNet. Full sources and licences.