A mathematician is a device for turning coffee into theorems.
Asked for a testimony to the effect that Emmy Noether was a great woman mathematician, he said: I can testify that she is a great mathematician, but that she is a woman, I
Possibly, on average, the smartest people around since they can actually back up their knowledge with rigorous proof. Someone who specializes in pure or applied mathematics.
A mathematician is not happy until the proof is complete.
A sexual act where one person (male or female) kneels at a man's side, and with the fingers of one hand probes the anus in a calculator-button pushing motion. The other hand grips the penis and strokes it in a crank handle fashion, as if he or she is operating an old-time crank-handle calculator.
Sally promised the college math professor that if she performed the mathematician on him he would shout out prime numbers at the top of his lungs.