insouciant

Adjective

• marked by blithe unconcern
  • an ability to interest casual students
    
  • showed a casual disregard for cold weather
    
  • an utterly insouciant financial policy
    
  • an elegantly insouciant manner
    
  • drove his car with nonchalant abandon
    
  • was polite in a teasing nonchalant manner
    

Related words

• Synonyms: 
  casual , nonchalant