stag·nant (stgnnt)
adj.
1. Not moving or flowing; motionless.
2. Foul or stale from standing: stagnant ponds.
3.
a. Showing little or no sign of activity or advancement; not developing or progressing; inactive: a stagnant economy.
b. Lacking vitality or briskness; sluggish or dull: a stagnant mind.