greyed out

adjective

(of a navigation button, menu item, etc on a computer screen) not highlighted, indicating that the function is unavailable at a given time

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012