This is a style in which people appear passive on the surface, but are actually acting out their anger in indirect or behind-the-scenes ways. Prisoners of War often act in passive-aggressive ways in order to deal with an overwhelming lack of power. People who behave in this manner usually feel powerless and resentful, and express their feelings by subtly undermining the object (real or imagined) of their resentments – even if this ends up sabotaging themselves. The expression "Cut off your nose to spite your face" is a perfect description of passive-aggressive behaviour.
(CRJ) Criminal Justice