Thing To Be not Do Today: fast.

So, what's the connection between fasting, as in not eating for a period of time, and being fast, as in Usain Bolt?

Um...well...they're spelled the same way...the other links might be older than the English language itself.

Anyway, while fast, as in not eating, has hardly changed its meaning for a thousand years, fast, as in moving quickly, has sprouted in all sorts of interesting ways. If you think about it, a door that's fast is very difficult to get to move at all, let alone quickly; someone who is fast seeks constant pleasure, but they might not move very far - and probably not at any sort of speed - in order to find it; a colour that's fast is staying the same and not going anywhere; and neither is someone who's fast asleep. A fast talker is probably playing fast and loose and pulling a fast one; and at archery a cry of fast! means stop!

But as I say, the roots of all this mess started a long long time ago.

Thing To Be Or Do Today: fast. The modern word that gives some clue about this divergence of meaning is steadfast, because fast started off in Old English as fæst, which meant firmly fixed, enclosed, strong, a word which probably goes right back to the Sanskrit word pastyam, which means dwelling place. From the idea of a strong runner, fast came to mean quick (though this didn't happen until the mid 1550s); and from the idea of a strong will, or strong discipline came the idea of not eating.