pearshaped

[loz]

Where does the saying pearshaped come from?

[sft42]

To go pear shaped is an expression used to indicate that a scheme has not been perfectly executed. The phrase seems to have originated in British English in the late 1940s or early 1950s. I have discovered several suggested origins, but the best, for me, is related to training aircraft pilots. At some stage they are encouraged to try to fly loops - very difficult to make perfectly circular; often the trainee pilot's loops would go pear shaped.

[JohnPPotts]

A (male) friend of mine said he thought it was from the shape women didn't want to go (ie. with a large posterior) - which seems as plausible a theory as any I've heard.