stagnate
Concise Oxford English Dictionary © 2008 Oxford University Press:
stagnate /stagˈneɪt, ˈstagneɪt/
▶verb become stagnant.
– derivatives
stagnation noun.
stagnation noun.
– origin C17: from L. stagnat-, stagnare ‘settle as a still pool’, from stagnum ‘pool’.
'stagnate' also found in these Oxford entries:

