to do something bad and not get punished or found out. (Informal when the something refers figuratively to murder.)
Tom did it again and didn't get punished. He's always getting away with murder.Just because she's so popular, she thinks she can get away with anything.You'll never get away with it.
Idiom
get away with somethingget away with (something)
to avoid blame, punishment, or criticism for doing something bad.
She cheated on the test and thought she could get away with it.