1. Become quiet or calm, especially after a state of agitation
   - calm, cool off, chill out, simmer down, settle down, cool it, wind down, take a chill pill 
2. Make calm or still
   - calm, quiet, tranquilize [N. Amer], tranquillize, tranquillise [Brit], quieten, lull, still 
3. Become quiet or less intensive
   - lull

Derived forms: calms down, calming down, calmed down

Type of: change state, comfort, console, hush, hush up, quieten, shut up, silence, solace, soothe, still, turn

• negative reinforcing stimulus
• negative stimulation
• negative stimulus
• negatively
• negatively charged
• negativeness
• negativism
• negativist
• negativity
• negatory
• negatron
• Negev
• Negev Desert
• NegGram
• neglect
• neglect of duty
• neglected
• neglecter
• neglectful
• neglectfully
• neglectfulness
• negligee
• negligence
• negligent
• negligently