To get away with something is to do something wrong and never be punished for it. No consequences at all.
It is a three-part phrase and it stays together. It covers crimes and small liberties equally, so getting away with murder is the fixed hyperbole for behaviour nobody stops. There is a milder use about style, since somebody who can get away with a bold jacket is somebody it suits. The phrase always implies that punishment or criticism was deserved and did not arrive.
1phraseget away withTo escape blame or punishment for something.
“He seems to get away with it every single time.”