To touch or cover with the thumb.
to thumb the touch-hole of a cannon
(with through) To turn the pages of (a book) in order to read it cursorily.
I thumbed through the book and decided not to bother reading it all.
(travel) To hitchhike
So I started thumbin' back east, toward my hometown.
To soil or wear with the thumb or the fingers; to soil, or wear out, by frequent handling.
To manipulate (an object) with the thumb; especially, to pull back the hammer or open the cylinder of a revolver.
To fire (a single action revolver) quickly by pulling the hammer while keeping the trigger depressed.
The act by which something is thumbed.