splash guard vs splash-guard

splash guard and splash-guard both are nouns.

Word	Noun	Adjective	Verb	Adverb
splash guard	Yes	No	No	No
splash-guard	Yes	No	No	No

As nouns, splash guard and splash-guard are synonyms defined as:

splash guard and splash-guard: a curved piece above the wheel of a bicycle or motorcycle to protect the rider from water or mud thrown up by the wheels

Other synonyms of splash guard include mudguard.

splash guard (noun)	splash-guard (noun)
a curved piece above the wheel of a bicycle or motorcycle to protect the rider from water or mud thrown up by the wheels	a curved piece above the wheel of a bicycle or motorcycle to protect the rider from water or mud thrown up by the wheels