fillet of sole vs sole

fillet of sole and sole both are nouns.

Word	Noun	Adjective	Verb	Adverb
fillet of sole	Yes	No	No	No
sole	Yes	Yes	Yes	No

As nouns, fillet of sole and sole are synonyms defined as:

fillet of sole (noun)	sole (noun)
lean flesh of any of several flatfish	right-eyed flatfish; many are valued as food; most common in warm seas especially European
	the underside of footwear or a golf club
	the underside of the foot
	lean flesh of any of several flatfish

fillet of sole (adjective)	sole (adjective)
	being the only one; single and isolated from others
	not divided or shared with others

fillet of sole (verb)	sole (verb)
	put a new sole on