Proof vs. Poof
At a conference, someone taught me the difference between a Proof and a Poof.
That is, a Poof is a Proof with the R removed along with the Rigor!
The University of Toronto Math Department offers somewhat different interpretations, where a Poof is:
 A proof that sneaks up on you and hits you like an uncountable number of bricks, then gets erased off the board before it can be understood
 A highly improbable construction, usually nonconstructive, that produces the desired result by magically pulling a rabbit out of a hat
 Something which students produce, especially on exams, when asked to give a proof...and such students usually do not major in mathematics
QED....for Question Every Detail!
Source: Joel Chan's "As Easy as Pi," Math Horizons, Winter 1993, p. 19
