in·vol·un·tary /in-'vä-lən-ˌter-ē/ adj: done, made, or initiated contrary to or without one's choice
an involuntary confession
an involuntary lien
an involuntary plaintiff joined in the action
in·vol·un·tar·i·ly adv
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.