wheel horse vs wheeler

wheel horse and wheeler both are nouns.

Word	Noun	Adjective	Verb	Adverb
wheel horse	Yes	No	No	No
wheeler	Yes	No	No	No

As nouns, wheel horse and wheeler are synonyms defined as:

wheel horse and wheeler: a draft horse harnessed behind others and nearest the wheels of a vehicle

wheel horse (noun)	wheeler (noun)
a draft horse harnessed behind others and nearest the wheels of a vehicle	a draft horse harnessed behind others and nearest the wheels of a vehicle
	someone who makes and repairs wooden wheels
	a person who rides a bicycle
	the man at the outermost end of the rank in wheeling