signature has 4 distinct synonyms spread across 3 of its 5 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.
your name written in your own handwriting
Synonyms, antonyms and the broader and narrower relations for signature come from Princeton University’s WordNet. Full sources and licences.
a distinguishing style
“this room needs a woman's touch”
a melody used to identify a performer or a dance band or radio/tv program
the sharps or flats that follow the clef and indicate the key
a sheet with several pages printed on it; it folds to page size and is bound with other signatures to form a book