shire horse vs shire

shire horse and shire both are nouns.

Word	Noun	Adjective	Verb	Adverb
shire horse	Yes	No	No	No
shire	Yes	No	No	No

As nouns, shire horse and shire are synonyms defined as:

shire horse (noun)	shire (noun)
British breed of large heavy draft horse	British breed of large heavy draft horse
	a former administrative district of England; equivalent to a county