notice has 18 distinct synonyms spread across 7 of its 11 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 ignore.
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.
an announcement containing information about an event
“you didn't give me enough notice”
the act of noticing or paying attention
“he escaped the notice of the police”
a request for payment
“the notification stated the grace period and the penalties for defaulting”
polite or favorable attention
“his hard work soon attracted the teacher's notice”
a short critical review
“the play received good notices”
express recognition of the presence or existence of, or acquaintance with
“He never acknowledges his colleagues when they run into him in the hallway”
Synonyms, antonyms and the broader and narrower relations for notice come from Princeton University’s WordNet. Full sources and licences.