English to English

adjective (a)

• not consistent with or according to a constitution; contrary to the U.S. Constitution(adj.all)

  Antonym:
  constitutional
  

  source: wordnet30
• Not constitutional; not according to, or consistent with, the terms of a constitution of government; contrary to the constitution; as, an unconstitutional law, or act of an officer.(adjective)

  source: webster1913