Loose and lose are two words that often cause confusion among English writers because they not only look similar but also sound similar. Sometimes, people tend to use the term loose when they really wanted to mean lose.
The word lose can only be used as a verb to mean “to be deprived of or cease to have or retain something” or “to become unable to find something or someone.”
“Queen’s granddaughter Zara Tindall and her husband Mike lose their baby”
Telegraph.co.uk“Shorthanded Clippers Lose Third Straight Game, 106-102, Without Stars”
NBC Southern California“Why HTC’s Top-Ranked Virtual Reality Gear Will Lose Market Share In 2017”
Forbes
On the other hand, the term loose is an adjective meaning “not firmly or tightly fixed in place; detached or able to be detached” or “not fitting tightly or closely.”
“Charges laid after loose cheetah found wandering Kootenays highway”
Vancouver Sun“Labelling norms for loose garments relaxed”
Business Standard“Loose bracket caused F-35B fire”
Flight Global
Meanwhile, the term can also be used in the phrase on the loose to denote “having escaped from confinement.”
“Cops trying to catch giant ostrich-like rhea bird on the loose in Cambridgeshire”
The Sun“Berlin Christmas market attack killer still on the loose, say police”
The Guardian“‘Chilling’: A serial animal killer may be on the loose in Canada, mutilating pets, wildlife”
Washington Post
One simple way to remember which word to use is that when you mean something is not firmly fixed, then you have two o’s, so you use loose but when one of the o’s become missing, then you lose that o.