EXACERB'ATE, verb transitive [Latin exacerbo, to irritate; ex and acerbo, from acerbus, severe, bitter, harsh, sour. See Harvest.] 1. To irritate; to exasperate; to inflame angry passions; to imbitter; to increase malignant qualities. 2. To increase the violence of a disease.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI