on the nail

prepositional phrase2

1. •
   (UK, Ireland) Exactly.

   • Six o'clock on the nail. She wasn't going to be late. — 2009
2. •
   (UK, Ireland) Immediately, without delay.

   • Tell me, have you a mind to anything in the Doctor's book? Speak the word, and I will help you to it upon the nail. — 1596