bow leg vs bandy legs

bow leg and bandy legs both are nouns.

Word	Noun	Adjective	Verb	Adverb
bow leg	Yes	No	No	No
bandy legs	Yes	No	No	No

As nouns, bow leg and bandy legs are synonyms defined as:

Other synonyms of bow leg include bow legs.

bow leg (noun)	bandy legs (noun)
a leg bowed outward at the knee (or below the knee)	outward curvature of the legs
outward curvature of the legs