Not digestible physically; unassimilable, as food.
Not digestible mentally; not to be assimilated by the mind; not to be stomached or brooked; incomprehensible or unendurable: as, an indigestible statement; an indigestible affront.
the GNU version of the Collaborative International Dictionary of English
adjective.
Not digestible; not readily soluble in the digestive juices; not easily convertible into products fitted for absorption.
adjective.
Not digestible in the mind; distressful; intolerable.