What does "unconstitutional" mean?

Contrary to or violative of the constitution of a state or other sovereign institution.

What is a synonym for "unconstitutional"?

Common synonyms include: actionable, against the law, anarchic, anarchistic, anomic, black market.

adj

adj ·6 syllables ·Rare ·Advanced level

Adjective

1
Contrary to or violative of the constitution of a state or other sovereign institution.
"That recently passed political bill has been declared unconstitutional."

Adjective

1
not consistent with or according to a constitution; contrary to the U.S. Constitution wordnet

"Prime Minister Koizumi said, "There are people who say that, because it's unconstitutional, I should not pray at the Yasukuni Shrine"."

From un- + constitutional.