early 14c., concelen, "to keep close or secret, forbear to divulge," from Old French conceler "to hide, conceal, dissimulate," from Latin concelare "to hide," from con-, here perhaps an intensive prefix (see con-), + celare "to hide" (from PIE root *kel- (1) "to cover, conceal, save"). From early 15c. as "to hide or shield from observation." Replaced Old English deagan. Related: Concealed; concealing; concealable.