The term 'highly offensive' can be summarized by two crossword solutions: RANK (4 letters) and ODIOUS (6 letters). RANK is an adjective meaning of the worst kind, or of the lowest quality. It is often used to describe something that is extremely unpleasant or objectionable. ODIOUS is an adjective meaning arousing strong dislike or intense displeasure. It is often used to describe something that is morally reprehensible or deeply offensive.