cygnine adjective 2noun 1forms 2 adjective2 •Being of the genus Cygnus (swans), within subfamily Anserinae of the family Anatidae, though sometimes considered a distinct subfamily, Cygninae.The genus Choristopus, Eyton, apparently Anserine rather than Cygnine, is said to possess this character […] — 1869 •Of, concerning, relating to, resembling, or characteristic of swans.But, in the cutting of it, if thou dost shed / One drop of cygnine blood, thy clumsiness... — 1848 noun1 •(old-fashioned) An alkaloid from plants of genus Gastrolobium, found in Australia, principally Western Australia, highly toxic to introduced animals. formsmore cygnine · most cygnine