adj.
  - hard but liable to break easily.
- (of a voice) unpleasantly hard and sharp and showing signs of nervousness or instability.
n.
 a brittle sweet made from nuts and set melted sugar.
Derivative
  
    - brittlely 
(or brittly)
 adv.
- brittleness n.
 
  Etymology
  ME, ult. of Gmc origin and rel. to OE brēotan ‘break up’.