Antonyms of adj nugatory

1 sense of nugatory

Sense 1
nugatory -- (of no real value; "a nugatory law")

INDIRECT (VIA worthless) -> valuable -- (having great material or monetary value especially for use or exchange; "a valuable diamond")

Similarity of adj nugatory

1 sense of nugatory

Sense 1
nugatory -- (of no real value; "a nugatory law")
       => worthless (vs. valuable) -- (lacking in usefulness or value; "a worthless idler")