As nouns the difference between foreignness and foreignism
is that foreignness is (uncountable) the quality of being, appearing, or being perceived as foreign; exoticness, otherness while foreignism is a trait, custom, phrase or characteristic typical of a foreign country or language.
foreignness
English
Noun
(uncountable) The quality of being, appearing, or being perceived as foreign; exoticness, otherness.
(countable) A characteristic that indicates foreignness.
foreignism
English
Noun
(
en noun)
A trait, custom, phrase or characteristic typical of a foreign country or language.