check has 73 distinct synonyms spread across 23 of its 38 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. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
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.
examine so as to determine accuracy, quality, or condition
“check the brakes”
make an examination or investigation
“check into the rumor”
stop for a moment, as if out of uncertainty or caution
“She checked for an instant and missed a step”
block or impede (a player from the opposing team) in ice hockey
develop (a child's or animal's) behavior by instruction and practice; especially to teach self-control
“Parents must discipline their children”
consign for shipment on a vehicle
“check your luggage before boarding”
hand over something to somebody as for temporary safekeeping
“Check your coat at the door”
abandon the intended prey, turn, and pursue an inferior prey
stop in a chase especially when scent is lost
“The dog checked”
place into check
“He checked my kings”
write out a check on a bank account
verify by consulting a source or authority
“check the spelling of this word”
a written order directing a bank to pay money
“he paid all his bills by check”
Synonyms, antonyms and the broader and narrower relations for check come from Princeton University’s WordNet. Full sources and licences.
additional proof that something that was believed (some fact or hypothesis or theory) is correct
“fossils provided further confirmation of the evolutionary theory”
the act of inspecting or verifying
“they made a check of their equipment”
a mark indicating that something has been noted or completed etc.
“as he called the role he put a check mark by each student's name”
something immaterial that interferes with or delays action or progress
a textile pattern of squares or crossed lines (resembling a checkerboard)
“she wore a skirt with checks”
obstructing an opponent in ice hockey
(chess) a direct attack on an opponent's king