'tweak' originates from English, first recorded in the early 16th century; it is likely of imitative or echoic origin representing a sharp twist, pull, or pinch.

'tweak' appeared in earlier English/Middle English forms (recorded as variants such as 'tweken'/'tweck') meaning to pluck, pinch, or pull; over time these senses developed into the modern verbal and nominal uses.

Initially it meant 'to pinch, pluck, or twist sharply'; over time the sense broadened to include 'make small adjustments' or 'fine-tune' in technical and everyday contexts.