You lose your keys.
You lose a bet.
You lose weight so your clothes have a more loose fit.
You have a screw loose and are a bit of a loser.
You ask a strong man to loosen a tight jar, but lose track of time watching his muscles.
AAAHHHHHHH!!! Get it straight, people.

Here's a not-so-friendly comic on the subject (f-bombs):
http://www.queenofwands.net/d/20050909.html