Antonyms of adj yummy

1 sense of yummy

Sense 1
delectable, delicious, luscious, pleasant-tasting, scrumptious, toothsome, yummy -- (extremely pleasing to the sense of taste)

INDIRECT (VIA tasty) -> tasteless -- (lacking flavor)

Similarity of adj yummy

1 sense of yummy

Sense 1
delectable, delicious, luscious, pleasant-tasting, scrumptious, toothsome, yummy -- (extremely pleasing to the sense of taste)
       => tasty (vs. tasteless) -- (pleasing to the sense of taste; "a tasty morsel")