plum and plumb

In a discussion on the attempts to curb the propensity of politicians to give jobs to their mates, I saw a reference to a plumb job. Some research online, even allowing for many jokes about plumbers getting plumb jobs, showed that there was a tendency to confuse plumb with plum.

The idea of something desirable being regarded as a juicy plum goes back to the early 1800s in British English.  It brings to mind Little Jack Horner who put in his thumb and drew out a plum from the Christmas pudding.

Plumb, on the other hand, is all about lead weights (from Latin plumbum).  A plumb is a lump of lead used as a weight as on a fishing line or in a clock.  A plumb line (a string with a lump of lead at the bottom) gives you a straight vertical line. So plumb came to mean ‘straight, in correct alignment’.  And it is from this sense of plumb that we get expressions like plumb crazy, that is, ‘straight crazy’.   

Funnily enough the expression is turning up as plum crazy.

Our plums and plumbs are spinning around in a way that’s plumb loco.