Bench legs are the equivalent of shapeless, unattractive calves on a woman. Also, it denotes almost no leg definition between knee and ankle. This phrase was the early forerunner to "cankles" used more commonly in the 1980's and 1990's. For instance, Hillary Clinton has bench legs.
That gal walking toward us has ugly and unshapely bench legs!
by Flannery O'Connor July 27, 2011