STAGNANT meaning : 1. (of water or air) not flowing or moving, and smelling unpleasant: 2. not growing or developing…. Learn more. The meaning of STAGNANT is not flowing in a current or stream. How to use stagnant in a sentence. Discover everything about the word " STAGNANT " in English: meanings, translations, synonyms, pronunciations, examples, and grammar insights - all in one comprehensive guide. 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