Disingenuous, a.
1. Not noble; unbecoming true honor or dignity; mean; unworthy; as, disingenuous conduct or schemes.
2. Not ingenuous; wanting in noble candor or frankness; not frank or open; uncandid; unworthily or meanly artful. So disingenuous as not to confess them [faults]. Pope. -- Dis`in*gen"u*ous*ly, adv. T. Warton. -- Dis`in*gen"u*ous*ness, n. Macaulay.
Shades of meaning
Fernald lists disingenuous only as an antonym, under honest.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given