Despite my opponent's personal attacks against me, I refuse to 'stoop to his level'. [=I refuse to behave as badly as he has by attacking him personally]
She would never 'stoop' to lying. [=she would never lie; she is too good a person to lie]
His shoulders are 'stooped'. [=his shoulders are bent forward]
(..) And the dummy fell for it... hook, line and sinker! And he still thinks we're his friends. And did Stromboli pay... plenty! That shows you how low HonestJohn will stoop, eh, Giddy? Now, uh, coachman, what's your proposition? Well, how would you blokes like to make some real money? (..)1940 Pinocchio