One means to fail to keep something, the other means not tight.
"Lose" (/luːz/) is the verb to misplace, be defeated, or fail to keep something. "Don't lose your keys" = do not misplace your keys. Past tense: "lost".
I always lose my phone charger.
We cannot afford to lose this client.
Did you lose your wallet again?
"Loose" (/luːs/) is the adjective meaning not tight or not firmly fixed. "A loose screw" = a screw that is not tightly fastened. Also the verb to loosen, though this use is less common.
The screw came loose and the shelf fell.
These jeans are too loose around the waist.
Her hair was loose and flowing in the breeze.
Common mistake
Trick to remember it
Quick rule
Did you know?
LOOSE also exists as a formal verb meaning to release or discharge: "to loose an arrow" is perfectly correct archaic English. However, this usage is so rare in modern English that when someone writes "loose" as a verb today, it is almost always a spelling mistake for "lose." Spell-checkers do not flag it as an error because both words are legitimate, which makes this pair one of the hardest to catch automatically. The word "loosen" (to make less tight) comes from LOOSE and is indeed common: "loosen your tie," "loosen up."
Exercise 1 · Pick the right one
Don't _____ your ticket! You'll need it to get back in.
Exercise 2 · Pick the right one
These trousers are too _____. I need a smaller size.
Exercise 3 · Form the word
One means to receive or agree to something, the other means to exclude or not include.
'Advice' is the guidance you receive (noun); 'advise' is the act of giving that guidance (verb).
'Affect' is the verb meaning to influence something; 'effect' is the noun meaning result or consequence.
'Aisle' is the walkway between rows of seats or shelves; 'isle' is a small island.
Bryan López
Founder of SpeakUP Academy