Compare Middle Chinese 快 (MC khwaejH). Cognate with Thai ไว (wai), Northern Thai ᩅᩮᩥ᩠ᨿ or ᩅᩰᩫ᩠ᨿ, Lü ᦺᦞ (vay), Shan ဝႆး (wái), Tai Nüa ᥝᥭᥰ (wäy), Ahom 𑜈𑜩 (bay).
ໄວ • (wai) (abstract noun ຄວາມໄວ)