S: (v) frighten, fright, scare, affright (cause fear in) "The stranger who hangs around the building frightens me"; "Ghosts could never affright her"
Adjective
S: (adj) awful, dire, direful, dread, dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terrible (causing fear or dread or terror) "the awful war"; "an awful risk"; "dire news"; "a career or vengeance so direful that London was shocked"; "the dread presence of the headmaster"; "polio is no longer the dreaded disease it once was"; "a dreadful storm"; "a fearful howling"; "horrendous explosions shook the city"; "a terrible curse"