1. Extremely and sharply
   - bitterly, bitingly, bitter 
2. In a shrill voice
   - shrilly

See also: piercing

• nitrobenzene
• nitrocalcite
• nitrocellulose
• nitrochloroform
• nitrochloromethane
• nitrocotton
• nitrofuran
• nitrofurantoin
• nitrogen
• nitrogen balance
• rerebrace
• rerecord
• reredos
• rerun
• RES
• res adjudicata
• res gestae
• res ipsa loquitur
• res judicata
• res publica
• resale
• resaw
• rescale
• reschedule
• rescind