Merriam-Webster's Collegiate® Dictionary, 11th Edition
BRITTLE
I. adjective (brittler; brittlest)
Etymology: Middle English britil; akin to Old English brēotan to break, Old Norse brjōta
Date: 14th century
1. easily broken, cracked, or snapped , easily disrupted, overthrown, or damaged ; frail ,
2. perishable , mortal , transitory , evanescent , easily hurt or offended ; sensitive , sharp , lacking warmth, depth, or generosity of spirit ; cold , affected with or being a form of type 1 diabetes characterized by large and unpredictable fluctuations in blood glucose level, see: fragile brittlely adverb brittleness noun
II. noun
Date: 1913
a candy made with caramelized sugar and nuts spread in thin sheets