This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “Cognate with Japanese きつい(kitsui, “narrow; harsh”) despite phonology and semantics? Compare 厳しい(kibishii, “narrow; harsh”). Accent is problematic: A-B-A (1. Tokyo 2. Kyoto 3. Kagoshima), and this seems to be a tone class B adjective (Yonaguni accent is irregular, probably a loanword from Okinawan).”