Meaning of “nail” - Learner’s Dictionary

nail

verb uk us /neɪl/
nail sth down/on/to, etc

to fasten something with nails:

There was a 'private property' sign nailed to the tree.

[ T ] mainly US informal to catch someone who has committed a crime:

They eventually nailed him for handling stolen goods.

(Definition of “nail verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)