'loather' originates from Old English, specifically the word 'lāðian,' where 'lāð' meant 'hateful.'

'lāðian' transformed into the Middle English word 'lothen,' and eventually became the modern English word 'loathe,' from which 'loather' is derived.

Initially, it meant 'to be hateful,' but over time it evolved into its current meaning of 'to intensely dislike or detest.'