generalissimo vs commander in chief

generalissimo and commander in chief both are nouns.

Word	Noun	Adjective	Verb	Adverb
generalissimo	Yes	No	No	No
commander in chief	Yes	No	No	No

As nouns, generalissimo and commander in chief are synonyms defined as:

generalissimo and commander in chief: the officer who holds the supreme command

Other synonyms of generalissimo include commander-in-chief.

generalissimo (noun)	commander in chief (noun)
the officer who holds the supreme command	the officer who holds the supreme command