D defs.my
Entry 1 sense Webster, 1913

Unconcern

/ŭnˌ-kən-sẽrn'/ · Un·con·cern · IPA /ˌʌnkənsˈɜrn/
01 n. Want of concern; absence of anxiety; freedom from solicitude; indifference.
  1. 1.
    Want of concern; absence of anxiety; freedom from solicitude; indifference.
    “A listless unconcern, Cold, and averting from our neighbor's good.” Thomson.