Origin and history of worser

Old English læs (adv.) "less, lest;" læssa (adj.) "less, smaller, fewer" (Northumbrian leassa), from Proto-Germanic *laisizan (source also of Old Saxon, Old Frisian les "less;" Middle Dutch lise "soft, gentle," German leise "soft"), from PIE root *leis- (2) "small" (source also of Lithuanian liesas "thin") + comparative suffix.

From the first, the adverb has been used often with negatives (none the less). Much less "still more undesirable" is from 1630s. Formerly also "younger," as a translation of Latin minor, a sense now obsolete except in James the Less. Used as a comparative of little, but not related to it. The noun is Old English læsse.

comparative adjective, "more unfortunate or undesirable," also in reference to health, wealth, etc., Middle English werse, from Old English wiersa, wyrsa "more evil, culpable, sinful, unpleasant," etc., from Proto-Germanic *wers-izon-.

This is reconstructed (Watkins) to be comparative of PIE *wers- (1) "to confuse, mix up" (source also of Old High German werra "strife," Old Saxon werran "to entangle, compound;" see war (n.)).

Also used as a comparative of bad, evil, ill or as the opposite of better. Of things, "in less good condition, less valuable or perfect," by c. 1200.

The comparative adverb, "more evilly, in a way less good or desirable," is Old English wyrs. Also see worse (n.). Germanic cognates include Old Norse verri, Swedish värre, Old Frisian wirra, Old High German wirsiro, Gothic wairsiza "worse."

comparative suffix, from Old English -ra (masc.), -re (fem., neuter), from Proto-Germanic *-izon (cognates: Gothic -iza, Old Saxon -iro, Old Norse -ri, Old High German -iro, German -er), from PIE *-yos-, comparative adjective suffix. Originally also with umlaut change in stem, but this was mostly lost in Old English by historical times and has now vanished (except in better and elder).

For most comparatives of one or two syllables, use of -er seems to be fading as the oral element in our society relies on more before adjectives to express the comparative; thus prettier is more pretty, cooler is more cool [Barnhart].