late 14c., "condition of external unhappiness," from Old French misere "miserable situation, misfortune, distress" (12c.), from Latin miseria "wretchedness," from miser (see miser). Meaning "condition of one in great sorrow or mental distress" is from 1530s. Meaning "bodily pain" is 1825, American English.
The word miserecordia, meaning "mercy," also derives from this root, "to resonate, or have compassion with the miserable."