French word celui-ci comes from French celui (The one.), French -ci (This: always used with ce or pronouns such as celui, celle.)

Detailed word origin of celui-ci

Dictionary entry	Language	Definition
celui	French (fra)	The one.
-ci	French (fra)	This: always used with ce or pronouns such as celui, celle.
celui-ci	French (fra)	The latter. This one.