Definition of extenuates:
(v) :
(archaic) (specifically) To diminish or seek to diminish the extent or severity of (a crime, guilt, a mistake, or something else negative) by making apologies or excuses; to palliate.
(adj) :
Of a quality or thing: lessened, weakened.
(v) :
(archaic) To underestimate or understate the importance of (something); to underrate.
(v) :
To make (something) less dense, or thinner; also, to lower the viscosity of (something).
(adj) :
Of a person: emaciated, wasted, weakened; of the body or part of it: atrophied, shrunken, withered.
(v) :
(archaic) To make (someone or something) slender or thin; to emaciate, to waste.