These words refer to a caustic, sharp or rancorous temper or manner. Bitterness can indicate, most generally, a gloomy, dour or cold disposition, but its special connotations suggest a deep-seated rage directed inwards more than an anger directed at others, with disillusion or a conviction of injustice as its possible source and a smouldering cynicism as its possible result: lifelong bitterness at losing the woman he loved. Sourness is less intense than bitterness but suggests somewhat the same dour manner with an inward-directed disillusion as its source: What was sourness in Hamlet’s view of the world has deepened to bitterness in Timon’s. On the other hand, sourness , unlike bitterness , might suggest an external appearance only: a cheerful disposition that belied the sourness of her wrinkled face. Harshness relates more to manner than to disposition, suggesting not so much rancour as cruelty, either deliberate or unintentional: a teacher who met every infraction of the rules with harshness . Harshness , however, might merely be employed as a tactic: trying to soften his will first with wheedling, then with harshness .

The remaining words have a greater degree of formality than the foregoing. Acerbity relates most closely to sourness, suggesting an acidity of attitude that might, however, be expressed by a more directly sharp manner than with sourness : the abrupt acerbity with which he countered our every attempt at a casual conversation. Asperity relates most closely to harshness , with special emphasis on roughness or severity of treatment; implying even an arbitrary unevenness of disposition: the bewildering asperity of a governess who first ignored his questions and then punished him for asking them. Acrimony relates most closely to bitterness , but with a more outwardly directed rancour implied, even to the point of biting, irritating and enraged actions: trying to make peace in a charged atmosphere clouded by acrimony .