Definition of "Stagnate" :
verb: be idle; exist in a changeless situation
"The old man sat and stagnated on his porch."
verb: cease to flow; stand without moving
"Blood stagnates in the capillaries."
verb: cause to stagnate
"There are marshes that stagnate the waters."
verb: stand still
"Industry will stagnate if we do not stimulate our economy."