"sour" en el diccionario Collins English Cobuild & Thesaurus

sour
adj

1 acerb, acetic, acid, acidulated, bitter, pungent, sharp, tart, unpleasant

2 bad, curdled, fermented, gone off, rancid, turned, unsavoury, unwholesome

3 acrid, acrimonious, churlish, crabbed, cynical, disagreeable, discontented, embittered, grouchy (informal) grudging, ill-natured, ill-tempered, jaundiced, peevish, tart, ungenerous, waspish
vb

4 alienate, disenchant, embitter, envenom, exacerbate, exasperate, turn off  (informal)

Antonyms
,   adj

1 agreeable, bland, mild, pleasant, savoury, sugary, sweet

2 fresh, unimpaired, unspoiled

3 affable, amiable, congenial, friendly, genial, good-humoured, good-natured, good-tempered, pleasant, warm-hearted
vb enhance, improve, strengthen