serjeant-at-arms vs sergeant at arms

serjeant-at-arms and sergeant at arms both are nouns.

Word	Noun	Adjective	Verb	Adverb
serjeant-at-arms	Yes	No	No	No
sergeant at arms	Yes	No	No	No

As nouns, serjeant-at-arms and sergeant at arms are synonyms defined as:

serjeant-at-arms and sergeant at arms: an officer (as of a legislature or court) who maintains order and executes commands

serjeant-at-arms (noun)	sergeant at arms (noun)
an officer (as of a legislature or court) who maintains order and executes commands	an officer (as of a legislature or court) who maintains order and executes commands