outboard vs outboard motor

outboard and outboard motor both are nouns.

Word	Noun	Adjective	Verb	Adverb
outboard	Yes	Yes	No	No
outboard motor	Yes	No	No	No

As nouns, outboard and outboard motor are synonyms defined as:

outboard and outboard motor: internal-combustion engine that mounts at stern of small boat

outboard (noun)	outboard motor (noun)
internal-combustion engine that mounts at stern of small boat	internal-combustion engine that mounts at stern of small boat
a motorboat with an outboard motor

outboard (adjective)	outboard motor (adjective)
located away from the midline of a vessel or aircraft