mid-13c., wersnen "to make worse," also "to grow worse," from worse (adj.) + -en (1). The reflexive sense of "to get worse, become worse off" was elevated into literary use c. 1800-30, where formerly worse (v.) had served. Related: Worsened; worsening.

"depreciative, disparaging, giving a low or bad sense to," 1888, from French péjoratif, from Late Latin peiorat-, past-participle stem of peiorare "make worse," from Latin peior "worse," perhaps originally "stumbling," from PIE *ped-yos-, suffixed (comparative) form of *ped- "to walk, stumble, impair," from root *ped- "foot." As a noun, "a word that depreciates the sense," from 1882. English had a verb pejorate "to worsen" from 1640s.