any expression or show of disapproval: a tax bill that received Congressional frowns.
Origin: 1350–1400; Middle English frounen < Old French froignier, derivative of froigne surly expression, probably < Gaulish *frognā; compare Welsh ffroen,Old Breton fron nostril, Old Irish srón nose < Celtic *srognā or *sroknā
late 14c., from O.Fr. froignier "to frown or scowl, snort," related to frongne "scowling look," probably from Gaulish *frogna "nostril" (cf. Welsh ffroen "nose"), with a sense of "snort," or perhaps "haughty grimace." Related: Frowned; frowning.
The noun is from 1580s.