1) Avert, archaically 2) Forbid 3) Prevent from happening 4) Prevent the occurrence of 5) To avert 6) To forbid 7) To prohibit 8) Ward off Found on https://www.crosswordclues.com/clue/forfend
For·fend' transitive verb [ Prefix for- + fend . See Forewend .] To prohibit; to forbid; to avert. [ Archaic] « Which peril heaven forefend !» Shak. » This is etymologically the preferable spelling. Found on http://www.encyclo.co.uk/webster/F/62