Incesttuous \In*cest"tu*ous\ (?; 135), a. [L. incestuosus: cf. F. incestueux.] Guilty of incest; involving, or pertaining to, the crime of incest; as, an incestuous person or connection. --Shak. Ere you reach to this incestuous love, You must divine and human rights remove. --Dryden. -- {In*cest"tu*ous*ly}, adv. -- {In*cest"tu*ous*ness}, n.