stamp has 17 distinct synonyms spread across 10 of its 18 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.
a type or class
“more men of his stamp are needed”
a symbol that is the result of printing or engraving
“he put his stamp on the envelope”
a small adhesive token stuck on a letter or package to indicate that that postal fees have been paid
something that can be used as an official medium of payment
a small piece of adhesive paper that is put on an object to show that a government tax has been paid
a block or die used to imprint a mark or design
to mark, or produce an imprint in or on something
“a man whose name is permanently stamped on our maps”
Synonyms, antonyms and the broader and narrower relations for stamp come from Princeton University’s WordNet. Full sources and licences.
reveal clearly as having a certain character
“His playing stamps him as a Romantic”
treat or classify according to a mental stereotype
“I was stereotyped as a lazy Southern European”
destroy or extinguish as if by stamping with the foot
“Stamp fascism into submission”
form or cut out with a mold, form, or die
“stamp needles”
crush or grind with a heavy instrument
“stamp fruit extract the juice”