unconcerned
adj. B2 Upper Intermediate US //ˌənkənˈsɝnd// UK //ʌnkənsˈɜːnd// un·con·cerned
adj. not worried or interested in what is happening. You use this to describe someone who stays calm and relaxed even when there is a problem.
adj. lacking worry, interest, or anxiety. Often used to describe a person's attitude toward a specific situation or event.
He looked unconcerned even when the car broke down.
The manager remained unconcerned about the minor delays, as the final deadline was still weeks away.
Despite the mounting evidence against the suspect, the lead detective remained unconcerned, believing that the witness testimony would eventually prove unreliable under cross-examination.
From un- + concerned or unconcern + -ed.