Meaning : Stand still.
Example :
Industry will stagnate if we do not stimulate our economy.
Meaning : Cause to stagnate.
Example :
There are marshes that stagnate the waters.
Meaning : Cease to flow. Stand without moving.
Example :
Stagnating waters.
Blood stagnates in the capillaries.
Meaning : Be idle. Exist in a changeless situation.
Example :
The old man sat and stagnated on his porch.
He slugged in bed all morning.
Exert oneself by doing mental or physical work for a purpose or out of necessity.
I will work hard to improve my grades.