I was going to just link something, but after quite a Google search, I couldn’t find a good explanation on line that focused on just this issue (I found lots of hits, but none of them satisfied). It’s been bugging me for decades now (ever since I first went on line, and found so much misuse of the words). I don’t know if it’s a new phenomenon, or if we just see a lot more of it because we see a lot more people’s written material. I also don’t understand why it’s so hard for some people to get right, though perhaps because of the “oo” sound in “lose.” Anyway:

“Lose” = “to not win, or to misplace.”

“Loose” = “not tight, or not bound.”

“Loser” = “someone who has lost.”

“Looser” = “making less tight (or more loose).”

“Losing” = “in the process of achieving a loss, of a sporting event, or political race, or valuable assets.”

“Loosing” = “to set free (e.g., loosing the horses to let them run free, or loosing the dogs to chase a criminal).”

[Sunday update]

Behold, a blog devoted to needless quotation marks.