Definition of stagnant adjective in Oxford Advanced Learner's Dictionary. Meaning , pronunciation, picture, example sentences, grammar, usage notes, synonyms and more. stagnant (comparative more stagnant , superlative most stagnant ) Lacking freshness, motion, or flow; decaying through stillness. synonym Synonym: standing a stagnant pool stagnant water (figurative) Without progress or change; stale; inactive. a stagnant economy stagnant prices Stagnant means not flowing or moving, and often foul-smelling or stale, or showing little or no activity or vitality. Find the origin, usage, and examples of stagnant and related words in this online dictionary. Discover everything about the word " STAGNANT " in English: meanings, translations, synonyms, pronunciations, examples, and grammar insights - all in one comprehensive guide.