Antonyms of adj semiofficial

1 sense of semiofficial

Sense 1
semiofficial -- (having some official authority or sanction)

INDIRECT (VIA official) -> unofficial -- (not having official authority or sanction; "a sort of unofficial mayor"; "an unofficial estimate"; "he participated in an unofficial capacity")

Similarity of adj semiofficial

1 sense of semiofficial

Sense 1
semiofficial -- (having some official authority or sanction)
       => official (vs. unofficial) -- (having official authority or sanction; "official permission"; "an official representative")