Our commando's implied an interesting byway. In colloquial UK English at least, the word 'knock' has been given some particular meanings in simple combination:

Knock off: to end work or disengage from a task
Knock out: to render senseless
Knockout: 'drop-dead gorgeous' (Guru has a boring 'strikingly attractive')
Knock up: to impregnate
Knock up: also, to wake factory or mine workers
(the task was given to a 'knocker-up')
Knock-off: an article manufactured as a cheap copy of the original

There are others, too - are these shared around the world, or do some of them have similar structures for quite different meanings? Does anyone have a particular favourite?