Is it ensure, insure, or assure?
"a slobbering or dirty fellow, a worthless sloven," 1610s, from slubber "to daub, smear; behave carelessly or negligently" (1520s), probably from Dutch or Low German (cf. slobber (v.)). Second element appears to be an attempt to imitate French; or perhaps it is French, related to Old French goalon "a sloven." Century Dictionary speculates the -de- means "insignificant" or else is from hobbledehoy.