A plant, especially a tree, that defiantly grows in a place that it's not supposed to. Distinguished from a weed by growing in a extremely unexpected, unusual place. Commonly found on roofs.

Appeared in a Monty Python sketch:
"This is a wottle,
The emblem of our land
You can stick it in a bottle
You can hold it in your hand"

A water bottle

A polite way of saying "what the fuck"

Said in a typically posh English accent whilst flapping hands