exacerb

Exacerb is a verb that means to make something worse or more severe. In contemporary English, the standard verb is exacerbate, and forms derived from it—exacerbates, exacerbating, exacerbated—are widely used. Exacerb, by contrast, is rarely used and is often described as obsolete, archaic, or dialectal in modern dictionaries. When it does appear, it is typically treated as a back-formation or historical remnant rather than a productive part of current English.

Etymology traces exacerb to Latin roots related to harshness, passing into English through the prefix ex- and the idea of making something harsher or more severe. The dominant lineage in English is the verb exacerbate, with noun and adjective forms such as exacerbation and exacerbating.

Usage and nuance: exacerbate is commonly employed in both general and technical contexts, including medicine, policy, and social science. A sentence illustrating normal usage is: The drought exacerbated the water shortage. In medical writing, symptoms and conditions are said to be exacerbated or to have an exacerbation when they worsen. By contrast, exacerbb is not standard in modern prose and is likely to confuse readers, so it is generally avoided in favor of the established term.

See also: exacerbation, exacerbate, aggravate, worsen. Relative to synonyms, exacerbate emphasizes worsening that often has harmful or difficult implications, rather than mere growth or annoyance.