Not \Not\, adv. [OE. not, noht, nought, naught, the same word as E. naught. See {Naught}.] A word used to express negation, prohibition, denial, or refusal. Not one word spake he more than was need. --Chaucer. Thou shalt not steal. --Ex. xx. 15. Thine eyes are upon me, and I am not. --Job vii. 8. The question is, may I do it, or may I not do it? --Bp. Sanderson. {Not . . . but}, or {Not but}, only. [Obs. or Colloq.] --Chaucer.