Nail

1. To fasten with a nail or nails; to close up or secure by means of nails; as, to nail boards to the beams.
2. To stud or boss with nails, or as with nails.
3. To fasten, as with a nail; to bind or hold, as to a bargain or to acquiescence in an argument or assertion; hence, to catch; to trap.
4. To spike, as a cannon.
To nail an assertion or To nail a lie , etc.,
to detect and expose it, so as to put a stop to its currency; -- an expression probably derived from the former practice of shopkeepers, who were accustomed to nail bad or counterfeit pieces of money to the counter.