Unconcerned is a related term of unobservant.
As adjectives the difference between unconcerned and unobservant
is that unconcerned is indifferent and having no interest; aloof while unobservant is not observant.
unconcerned
English
Adjective
(
en adjective)
Indifferent and having no interest; aloof.
Not worried, anxious or apprehensive.
See also
* unencumbered
* unbothered
* carefree
unobservant
English
See also
*nonobservant
*inobservant