- slang an engineer's small screwdriver, used for fine adjustments
Examples from the Web for tweaker
I did wonder,' he said, 'whether you were such an innocent as really to believe it was a tweaker.'Life of Frederick Courtenay Selous, D.S.O.
McTurk read the papers of those years and could be trusted for general information, which he used as he used his "tweaker."Stalky & Co.