Frightful is a related term of unsightly.
As adjectives the difference between frightful and unsightly
is that frightful
is (obsolete): full of fright; affrighted; frightened while unsightly
is displeasing to the eye.
* frightfull (archaic)
(obsolete): Full of fright; affrighted; frightened.
Full of that which causes fright; exciting alarm; impressing terror; shocking; as, a frightful chasm, or tempest; a frightful appearance.
(Used as an intensifier)
- We wasted a frightful amount of money on renovations.
* The forms unsightlier and unsightliest are dated.