Overheated...
"Obnoxious" and "offensive" are the only ones I can think of.
There are no common synonyms that start with O. Some suggestions:orchidaceous / ostentatious (gaudy, showy)overwhelming / overpowering (irresistable)The word ogleable (watchable, attractive) seems to exist only informally.
Omphalos, but I don't think it has a standard adjectival form.
Synonyms for "horrible" that start with the letters G, O, B, L, I, and N include: G: Ghastly O: Outrageous B: Bad L: Lousy I: Intolerable N: Nasty These words convey a similar sense of something being extremely unpleasant or distressing.
Some words that start with the letter O are:oceanOddOdeofoffOfficeogreoldOliveOnoneOpalOppositeorOrangeorboreganoorganismorgasmorigamiotherotteroughtOxymoronoval
opinion
Ohio
Ozymandias
okra
Synonym=ball o' meat Antonym=cube o' veggies
Some happy words that start with O include: Overjoyed Optimistic Open-hearted
Some German words that start with the letter O are Opa, Oma and oberflächlich.