Bitterness
(1) the physical sense of taste;
(2) a figurative meaning in the objective sense of cruel, biting words; intense misery resulting from forsaking God, from a life of sin and impurity; the misery of servitude; the misfortunes of bereavement;
(3) more subjectively, bitter and bitterness describe emotions of sympathy;’ the sorrow of childlessness and of penitence, of disappointment; the feeling of misery and wretchedness, giving rise to the expression "bitter tears";
(4) the ethical sense, characterizing untruth and immorality as the bitter thing in opposition to the sweetness of truth and the gospel;
(5) Nu 5:18 the Revised Version (British and American) speaks of "the water of bitterness that causeth the curse." Here it is employed as a technical term.
Frank E. Hirsch