expedient has no recorded synonym. 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 inexpedient.
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.
serving to promote your interest
“was merciful only when mercy was expedient”
a means to an end; not necessarily a principled or ethical one
1 of the 3 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for expedient.
Synonyms, antonyms and the broader and narrower relations for expedient come from Princeton University’s WordNet. Full sources and licences.