fearful

Etymology

From Middle English ferful, fervol, equivalent to fear + -ful.

adj

1. Frightening; causing fear.
   In the later Hebrew midrash Lilith is presented as the woman who knows how to recite the fearful name of God to work calamity; that this little girl cries out the fearful name of the sun god and thereby causes an earthquake would indicate that this girl is linked in the structure of the myth with Lilith. 1981, William Irwin Thompson, The Time Falling Bodies Take to Light: Mythology, Sexuality and the Origins of Culture, London: Rider/Hutchinson & Co., page 184
2. Tending to fear; timid.
   a fearful boy
3. (dated) Terrible; shockingly bad.
   But every day after dinner, for an hour, we were all together, and then the Favourite and the rest of the Royal Hareem competed who should most beguile the leisure of the Serene Haroun reposing from the cares of State — which were generally, as in most affairs of State, of an arithmetical character, the Commander of the Faithful being a fearful boggler at a sum. 1859, Charles Dickens, The Haunted House
4. (now rare) Frightened; filled with terror.

adv

1. (dialect) Extremely; fearfully.
   “He is fearful handsome, as you know,” she said remorsefully, “you cannot imagine, Georgiana, the joy when I first fell in love with him.” 2009, Juliette Shapiro, Mr. Darcy's Decision: A Sequel to Jane Austen's Pride and Prejudice
   “It's a fearful strong charm needs dragon's blood,” he said plaintively. 2014, Diana Wynne Jones, The Chrestomanci series
   His Dardanelles expedition gave the Turk a fearful long start. 2014, Michael Brock, Eleanor Brock, Margot Asquith's Great War Diary 1914-1916