Russian-English translations for невозмути́мый

• cool
  Linen has made cool and breathable clothing for millennia
  If you have a reddish complexion, you should mainly wear cool colors
  His proposals had a cool reception
• deadpan
  a deadpan face or look
  The comedian remained deadpan.
  deadpan behaviour or speech
• nonchalant
  We handled the whole frenetic situation with a nonchalant attitude.
  He is far too nonchalant about such a serious matter.
• unflappable