bobtailed vs bobtail

bobtailed is not a noun while bobtail is a noun.

Word	Noun	Adjective	Verb	Adverb
bobtailed	No	Yes	No	No
bobtail	Yes	Yes	No	No

As adjectives, bobtailed and bobtail are synonyms defined as:

bobtailed (noun)	bobtail (noun)
	a short or shortened tail of certain animals
	large sheepdog with a profuse shaggy bluish-grey-and-white coat and short tail; believed to trace back to the Roman occupation of Britain

bobtailed (adjective)	bobtail (adjective)
having a short or shortened tail	having a short or shortened tail