Antonyms of adj excellent

1 sense of excellent

Sense 1
excellent, first-class, fantabulous, splendid -- (very good;of the highest quality; "made an excellent speech"; "the school has excellent teachers"; "a first-class mind")

INDIRECT (VIA superior) -> inferior -- (of low or inferior quality)

Similarity of adj excellent

1 sense of excellent

Sense 1
excellent, first-class, fantabulous, splendid -- (very good;of the highest quality; "made an excellent speech"; "the school has excellent teachers"; "a first-class mind")
       => superior (vs. inferior) -- (of high or superior quality or performance; "superior wisdom derived from experience"; "superior math students")