As adjectives the difference between untraditional and unconventional
is that untraditional is not traditional, or departing from tradition while unconventional is not adhering to convention or accepted standards.
As a noun unconventional is
something or someone that is unconventional.
unconventional
English
Adjective
(
en adjective)
Not adhering to convention or accepted standards
Out of the ordinary
Atypical
Noun
(
en noun)
Something or someone that is unconventional.