- shady (adj.)
[shady 词源字典]
- "affording shade," 1570s; "protected by shade," 1590s; from shade (n.) + -y (2). Meaning "disreputable" (1862) probably is from earlier university slang sense of "of questionable merit, unreliable" (1848). Related: Shadily; shadiness. Old English had sceadlic "shady, 'shadely.'"[shady etymology, shady origin, 英语词源]