变质

to degenerate; to deteriorate / (of food) to go bad; to go off / (geology) metamorphism

to change / to become different / to transform / to vary / rebellion

character / nature / quality / plain / to pawn / pledge / hostage / to question / Taiwan pr. [zhi2]

metamorphic rock (geology)

(idiom) to degenerate (morally); to become depraved

to degenerate (morally) (idiom) / to become depraved

metamorphism (geology)

perishable