modified
unsociable, silent, morose, dour, glum, sulky, sour, cross, ill-humored, petulant, moody, grouchy, crabby, surly, fretful, ill-natured, ill-tempered, peevish, gloomy, gruff, querulous, churlish, saturnine, chumpish*, sourpussed*, fiddle-faced*; see also irritable.
Antonyms friendly*, sociable, jolly.