Finnish word idis comes from Finnish idea (Idea.), Finnish -is

Detailed word origin of idis

Dictionary entry	Language	Definition
idea	Finnish (fin)	Idea.
-is	Finnish (fin)	(colloquial) -er; a suffix used to form nouns and proper nouns from place names, common nouns and adjectives; gives a familiar nuance to the original word; the original word is often truncated in the process.
idis	Finnish (fin)	(slang) idea.

Words with the same origin as idis