SOUR Copy link • SOUR 1. adj., Not sweet, acerbus (opposed to mitis): amarus (opposed to dulcis: according to Döderlein, acerbus of a biting, amarus of a nauseous, bitterness: acerbus is far more commonly used, figuratively, of sour in words, character, etc.): acidus (opposed to dulcis; Vid: to taste or smell): acer (sharp). (The words are found in this connection and order.) acer acidusque. Somewhat sour, acidulus, subacidus. Very sour, acidissimus: peracerbus: acerbissimus: peracer: acerrimus (☞ malum acidum an apple sour, though ripe; malum acerbum, an apple sour, because unripe). To be sour, acere; acidum or acerbum, or acrem esse; gustatu acido or acri esse sapore. To be turning sour, acescere, coacescere: sour milk, lac acidum (Plin.): very sour vinegar, acetum acidissimum (Plin.). A sour grape, uva acerba (☞ not austera). Cross, ill-tempered, difficilis: morosus: tristis: sour looks, vultus acerbi (Ov.), severi (Mart.). To put on a sour look, acerbos sumere vultus (Ov.); severos ducere vultus (Mart.); frontem contrahere (Cic.); frontem attrahere, adducere (Sen.). To make sour, acidum facere. 2. v. Transitively, PROP., acidum facere. Figuratively, aliquem exacerbare. Intransitively, acescere: coacescere.