icy (adj.) Look up icy at Dictionary.com
Old English isig; see ice (n.) + -y (2). Modern use is said to be a late Middle English re-formation. Figurative sense "characterized by coldness or chill, frigid" (of manners, expressions, etc.) is from 1590s. Similar formation in Dutch ijzig, German eisig, Swedish isig. Related: Icily; iciness.