nasty
lousy
bad, beastly
synonym for the word horrible that starts with the letter o is offensive, or obnoxious.
nasty
yes notated
not good
nutty?
nauseous
Another word (synonym) for the word "unpleasant" that starts with an "h" is "horrific". Or at least that is what I could think of.
Abhorrent is a synonym for horrible. It begins with the letter A.
Active is a synonym for athletic. It starts with the letter a.
Bad, awful, and terrible are synonyms for horrible.