Unthinking is a related term of unobservant.
As adjectives the difference between unthinking and unobservant
is that unthinking is without proper thought; thoughtless while unobservant is not observant.
As a verb unthinking
is .
unthinking
English
Adjective
(
en adjective)
Without proper thought; thoughtless.
Showing no regard; careless or unconcerned.
Verb
(head)
unobservant
English
See also
*nonobservant
*inobservant