‘Lose’ and ‘loose’ are often mixed up, and this is understandable because there is only an ‘o’ of difference between them. They do not, however, have any meanings in common.
‘Loose’ is generally used as an adjective, the opposite of tight or contained.
The dog is running loose in the streets.
These jeans are loose around my waist.
‘Lose’ is a verb that means to suffer the loss of, to miss.
Don’t lose the car keys.
We cannot afford to lose this match.