In frightful, it is a sudden emotion; in dreadful, it is deeper and more prolonged; in awful, the fear is mingled with the emotion of awe, which subdues us before the presence of some invisible power.

Webster's Revised Unabridged Dictionary (1913)

Example sentences

scary Was it scary for you to live in the United States?
alarming The Gobi Desert is expanding at an alarming rate.
horrifying Santiago told Rima about his horrifying discovery.
hideous Some things get more hideous, when you clean them.
fearful “People are very fearful of the virus,” he added.

Popularity over time

Word	1850 → 2019	Trend
frightful		steady
scary		rising
alarming		steady
horrifying		rising
hideous		rising
fearful		rising

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: bad¹
4 letters: ugly², grim¹
5 letters: awful², scary²
6 letters: horrid², grisly²
7 letters: fearful², hideous³, ghastly²
8 letters: terrible³, horrible³, shocking², terrific³, horrific³, dreadful², alarming³, gruesome²
9 letters: monstrous², atrocious³
10 letters: tremendous³, horrifying⁴
11 letters: frightening³

The small number after each word is its number of syllables (ugly² = 2 syllables).

In other languages

Français: effrayant
Italiano: spaventoso
Español: espantoso