-mantic adj combining form forming adjectives corresponding to nouns ending in -mancy: necromantic. Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014man?tic (?mæn t?k) adj. 1. of or pertaining to divination. 2. having the power of divination. [1580?90;