sobriquet vs moniker

sobriquet and moniker both are nouns.

Word	Noun	Adjective	Verb	Adverb
sobriquet	Yes	No	No	No
moniker	Yes	No	No	No

As nouns, sobriquet and moniker are synonyms defined as:

sobriquet and moniker: a familiar name for a person (often a shortened version of a person's given name)

Other synonyms of sobriquet include byname, cognomen, nickname, soubriquet.

sobriquet (noun)	moniker (noun)
a familiar name for a person (often a shortened version of a person's given name)	a familiar name for a person (often a shortened version of a person's given name)