adjectivedialect, non standard, literary, archaic British, US
1More harmful, painful, offensive, unpleasant, or severe.
2Less good, not so good, inferior; of lower quality or value; less favourable, advantageous, or attractive; more unskilful or inefficient.
3Less well; more ill, distressed, or upset.
noundialect, non standard, literary, archaic British, US
1A person who or animal which is worse; one who is more wicked or inferior in qualities or performance.
2In plural. With possessive: a person's inferiors.
adverbdialect, non standard, literary, archaic British, US
1More badly, wickedly, or reprehensibly; more severely or harshly; more imperfectly, carelessly, or incorrectly.
2As an intensifier, with verbs of hurting, harming, hating, etc.: more greatly, severely, or intensely; in a greater degree.
Late 15th century; earliest use found in Trevisa's Bartholomeus De Proprietatibus Rerum. As adjective from worse + -er. As adverb from worse + -er.
1To make worse; = "worsen".
2To become worse; = "worsen".
Late 16th century; earliest use found in Thomas Rogers (c1553–1616), religious controversialist and Church of England clergyman. From worser, after better; perhaps reinforced by association with frequentative verbs in -er.