nonchalant

adj

1. Casually calm and relaxed.

   “We handled the whole frenetic situation with a nonchalant attitude.”

   “On the other hand, to arrive after dusk, when the multitude of garish little public-houses are lit up, giving glimpses of crowded jostling bars and taprooms, is an introduction to a fine city well calculated to affect even the most nonchalant.”

   “[…] The Mexican government's response to the American bombing was admirably laid back. General Enrique Diaz Gonzales and Consul General Raul Michel met with United States officials, who issued apologies and an invitation to come to "the next rocket shoot" at White Sands. The Mexican citizenry was similarly nonchalant. "Bomb Blast Fails to Halt Spring Fiesta," said the El Paso Times headline, noting that "many thought the explosion was a cannon fired for the opening of the fiesta."”

   “Undaunted by the occasion, Ruthe went on to become the first 15-year-old to run a sub-four-minute mile, even managing a nonchalant shrug of the shoulders as he crossed the finish line.”

2. Indifferent; unconcerned; behaving as if detached.

   “He is far too nonchalant about such a serious matter.”