(adv.) In a voluntary manner; of one's own will; spontaneously.

advisedly by choice by design calculatedly consciously contemplatedly deliberately designedly electively freely gratis gratuitously in cold blood independently intentionally knowingly meditatedly on purpose optionally pointedly premeditatedly purposefully purposely purposively spontaneously willfully willingly with full intent with intent with malice aforethought with purpose without coercion wittingly