adjective.
Lacking pretense or affectation; natural.
noun.
Someone not affected, as by a disease.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adjective.
free of artificiality; sincere and genuine
adjective.
unaware of or indifferent to
adjective.
undergoing no change when acted upon
adjective.
emotionally unmoved
Word Usage
"People don't like to believe this, but there is no way human beings can remain unaffected by what is done to other human beings, or even to animals who are not human."