[in.ef.fa.ble] adj [ME, fr. MF, fr. L ineffabilis, fr. in- + effabilis capable of being expressed, fr. effari to speak out, fr. ex- + fari to speak--more at ban] (14c) 1 a: incapable of being expressed in words: indescribable "~ joy" b: unspeakable "~ disgust"
2: not to be uttered: taboo "the ~ name of Jehovah" -- in.ef.fa.bil.i.ty n -- in.ef.fa.ble.ness n -- in.ef.fa.bly adv