10 letters · 16 points in Scrabble
originEtymology tree English grouchy Proto-Indo-European *-yōs Proto-Indo-European *-tHós Proto-Indo-European *-istHos Proto-Germanic *-istaz Proto-West Germanic *-ist Old English -est Middle English -est English -est English grouchiest From grouchy + -est.
Etymology from Wiktionary, CC BY-SA 3.0