fraternization vs fraternisation

fraternization and fraternisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
fraternization	Yes	No	No	No
fraternisation	Yes	No	No	No

As nouns, fraternization and fraternisation are synonyms defined as:

fraternization and fraternisation: associating with others in a brotherly or friendly way; especially with an enemy

fraternization (noun)	fraternisation (noun)
associating with others in a brotherly or friendly way; especially with an enemy	associating with others in a brotherly or friendly way; especially with an enemy