sanction has 11 distinct synonyms spread across 3 of its 7 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.
formal and explicit approval
“a Democrat usually gets the union's endorsement”
a mechanism of social control for enforcing a society's standards
official permission or approval
“authority for the program was renewed several times”
the act of final authorization
“it had the sanction of the church”
Synonyms, antonyms and the broader and narrower relations for sanction come from Princeton University’s WordNet. Full sources and licences.
give religious sanction to, such as through on oath
“sanctify the marriage”