9 letters · 15 points in Scrabble
noun the physical property of being inflexible and hard to bend
noun the property of moving with pain or difficulty
noun firm resoluteness in purpose or opinion or action
originFrom Middle English stiffenes, styffenesse, styfnesse; equivalent to stiff + -ness. Perhaps merging with Middle English stithnesse, stithnysse, from Old English stīþness (“stiffness”).
Etymology from Wiktionary, CC BY-SA 3.0