Is it ensure, insure, or assure?
mid-14c., from Old French corropt "unhealthy, corrupt; uncouth" (of language), and directly from Latin corruptus, past participle of corrumpere "to destroy; spoil," figuratively "corrupt, seduce, bribe," from com-, intensive prefix (see com-), + rup-, past participle stem of rumpere "to break" (see rupture (n.)). Related: Corruptly; corruptness.
mid-14c., "contaminate, impair the purity of," from Latin corruptus, past participle of corrumpere (see corrupt (adj.)). Late 14c. as "pervert the meaning of," also "putrefy." Related: Corrupted; corrupting.