Meaning of “stagnant” - Learner’s Dictionary

stagnant

adjective uk us /ˈstæɡnənt/
NO FLOW

Stagnant water or air does not flow and becomes dirty and smells unpleasant:

a stagnant pond
NO GROWTH

A stagnant economy, society, or organization does not develop or grow.

(Definition of “stagnant” from the Cambridge Learner’s Dictionary © Cambridge University Press)