un·con·cern 
(ŭn′kən-sûrn)
(ŭn′kən-sûrn)n.
1. Lack of interest; indifference.
2. Lack of worry or apprehensiveness.
[Probably back-formation from UNCONCERNED.]
- tiger moth
- tiger salamander
- tiger's-eye
- tiger's-eye
- tiger shark
- tiger shrimp
- tiger swallowtail
- Tighina
- tight
- tight ass
- tight-assed
- tighten
- tighten belt
- tight end
- tightener
- tighten (one's) belt
- tighten one's belt
- tightfisted
- tightfistedness
- tightlipped
- tight-lipped
- tightlippedness
- tightly
- tightness
- tightrope