I can't tell you how many times people blow this one. So let's see if we can't get it right.
When you provide a Las Vegas casino with additional revenue, you say, "Gee, I hate to lose money at the slots."
When the knot you've tied comes untied, you say, "Gee, I guess I tied that knot kind of loose."
So, any LOSS gets a single o — LOSE.
Anything that isn't tight gets a double o —L O O S E.
(And while we're sort of on the topic, I'd like to tell the otherwise wonderful comedian, Jim Gaffigan, that he needs a wheelbarrow to carry a Cinnabon, not a wheel barrel. Sheesh, Jim, get with the program!)