Definitions
1.verbTo touch or cover with the thumb."to thumb the touch-hole of a cannon"
2.verb(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."
3.verb(travel) To hitchhike"So I started thumbin' back east, toward my hometown."
4.verbTo soil or wear with the thumb or the fingers; to soil, or wear out, by frequent handling.
5.verbTo manipulate (an object) with the thumb; especially, to pull back the hammer or open the cylinder of a revolver.
6.verbTo fire (a single action revolver) quickly by pulling the hammer while keeping the trigger depressed.
7.nounThe act by which something is thumbed.