Adjectives

(s)fearfulexperiencing or showing fear“a fearful glance”, “fearful of criticism”
(s)awful, dire, direful, dread, dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terriblecausing 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”
(a)cowardly, fearfullacking courage; ignobly timid and faint-hearted“cowardly dogs, ye will not aid me then” (P.B.Shelley)
(s)fearful, frightfulextremely distressing“fearful slum conditions”, “a frightful mistake”
(s)fearful, timorous, trepidtimid by nature or revealing timidity“timorous little mouse”, “in a timorous tone”, “cast fearful glances at the large dog”