polite has 6 distinct synonyms spread across 2 of its 3 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 impolite.
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.
showing regard for others in manners, speech, behavior, etc.
marked by refinement in taste and manners
“cultivated speech”
not rude; marked by satisfactory (or especially minimal) adherence to social usages and sufficient but not noteworthy consideration for others
“even if he didn't like them he should have been civil”
Synonyms, antonyms and the broader and narrower relations for polite come from Princeton University’s WordNet. Full sources and licences.