declinal
(dɪˈklaɪnəl) nthe action of politely refusing or declining
adjgrammar (of parts of speech with inflected endings that correspond to case) having the ability to be inflected or declined
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014