indigestible adjective 2noun 1forms 3 adjective2 •Difficult or impossible to digest. •Difficult to accept; unpalatable. noun1 •Anything that is difficult to digest."Take a cruller, any way," said she, handing him a cake-basket containing a dozen or so of those unspeakable, Dutch indigestibles. — 1872 formsindigestibles · more indigestible · most indigestible