Emily Dickinson Lexicon

FALSE'LY, adv. [fols'ly.]

1. In a manner contrary to truth and fact; not truly; as, to speak or swear falsely; to testify falsely.
2. Treacherously; perfidiously. Swear to me – that thou wilt not deal falsely with me. Gen. xxi.
3. Erroneously; by mistake. Smallridge.