hideous

adjectives

grossly offensive to decency or morality; causing horror
"subjected to outrageous cruelty"; "a hideous pattern of injustice"; "horrific conditions in the mining industry"
hideous, horrid, horrific, outrageous
so extremely ugly as to be terrifying
"a hideous scar"; "a repulsive mask"
hideous, repulsive
is derived from
hideousness