Antonyms of adj serendipitous

1 sense of serendipitous

Sense 1
serendipitous -- (lucky in making unexpected and fortunate discoveries)

INDIRECT (VIA lucky) -> unlucky, luckless -- (having or bringing misfortune; "Friday the 13th is an unlucky date")

Similarity of adj serendipitous

1 sense of serendipitous

Sense 1
serendipitous -- (lucky in making unexpected and fortunate discoveries)
       => lucky (vs. unlucky) -- (having or bringing good fortune; "my lucky day"; "a lucky man")