Undemonstrative is a related term of apathetic.
As adjectives the difference between undemonstrative and apathetic
is that undemonstrative is not given to showing emotion or feelings; reserved or distant while apathetic is void of feeling; not susceptible of deep emotion; passionless; indifferent.
apathetic
English
Alternative forms
* apathetical
Adjective
(
en adjective)
Void of feeling; not susceptible of deep emotion; passionless; indifferent.
Of, or pertaining to apatheism.
Synonyms
* indifferent. impassive
Related terms
* apatheism
* apatheist