"he wrote a characteristically splenetic article": synonyms: bad-tempered, ill-tempered, ill-humored, angry, wrathful, cross, peevish, petulant, pettish, irritable, irascible, cantankerous, choleric, dyspeptic, testy, tetchy, snappish, waspish, crotchety, crabby, crabbed, querulous, resentful, rancorous, bilious, sour, bitter, acid, liverish; spiteful, malicious, ill-natured, hostile, acrimonious, malevolent, malignant, malign; informalbitchy; rareatrabilious, envenomed

Only used words make effective words. The unused ones remain in obscurity thus nobody knows their meaning.