'backlasher' originates from English, specifically formed from the noun 'backlash' + the agentive suffix '-er', where 'backlash' itself combines 'back' (meaning 'rear') and 'lash' (meaning 'a strike or sudden recoil').

'backlasher' is derived from the modern English compound 'backlash' (originally used in mechanical contexts in the 19th century for play or recoil between gears) with the addition of '-er' to indicate an agent, producing the sense 'one who causes or expresses a backlash.'

Initially, 'backlash' referred to a mechanical recoil or play; over time it acquired the figurative meaning of a strong adverse reaction, and 'backlasher' therefore came to mean 'a person who reacts adversely or provokes such a reaction.'