Up to no good

What is “Up to no good” means?
I have it from the statement " I solemnly swear that i’m up to no good".

Hi Savdasam,

If you are ‘up to no good’ it means you are doing something wrong or mischievous.

If you swear you are up to no good, then you are making an oath that you are doing something wrong. It’s unusual to see such a phrase as most people would want to indicate that they [/b]weren’t[/b] ‘up to no good’ in most circumstances. The person who says this wants to indicate that they are being ‘naughty’.
Where did you hear the phrase? Was it one of the ‘Harry Potter’ books?

Hello, Bev
I should think it was said in jest. After that the person must have burst out laughing. It was probably done in imitation of a real oath (oath of office for instance).

What does ‘up to no good’ means?[YSaerTTEW443543]

TOEIC short conversations: Directing phone calls[YSaerTTEW443543]

Hi Tort,

It is used extensively in the Harry Potter books, it is an oath required to open the a magical device called the ‘Marauder’s Map’. The witches and wizards are expected to be up to mischief in order to use this device.

I suspect that’s where Savdasam saw it.

You are right Beeesneees, it is an oath required to open the magical map in Harry Potter movie.
Thank you for your explanation,Beeesneees, and for your correction, Torsten.