c. 1400, "resembling skin," from skin (n.) + -y (2). Meaning "lean, emaciated" is recorded from c. 1600. Of clothes, "tight-fitting" by 1970. In the noun sense of "the truth" it is World War II military slang, perhaps from the notion of the "naked" truth. Related: skinniness.
例文
1. He set his skinny legs apart and threw back his shoulders.
彼は細い足を2本広げて、胸を強く張った。
2.You 're too skinny —we 'll have to fatten you up.