brain trick

English

Noun

brain trick (plural brain tricks)

1. (obsolete) A stratagem, a clever trick; a ruse.
   • 1613, John Marston, William Barksted, The Insatiate Countess, III.4:

     But do I not know these are but brain-tricks?

2. A delusion; a trick of the brain.
3. A puzzle designed to exercise the brain.