autoantonym means A word that has two opposing meanings. Lexicurio rates it Sui generis — a strength score of 90 out of 100.
Why “autoantonym” is a great word
AUTOANTONYM — [Noun] A word that contains two directly opposing meanings within itself. From the combining form auto- (meaning "self") + antonym (meaning "a word of opposite meaning"). Coined in 1960 by Joseph T. Shipley as 'autantonym'. Unlike "contronym" (a direct, later synonym from 1962) or "Janus word" (a metaphorical tag for duality), autoantonym emphasizes the paradox of a single term being its own enemy. It is "cleave" meaning to split apart and to cling tightly, "sanction" meaning to punish and to permit, or "dust" meaning to remove particles and to sprinkle them—a quiet testament to language's capacity to hold contradiction in a solitary, stable vessel, a permanent act of translation with oneself.
Etymology
From auto- + antonym. Coined or reported as autantonym by Joseph T. Shipley in 1960.
noun
- A word that has two opposing meanings.“Near-synonym: enantioseme”