- Old hand ( at sth. / at doing sth.) : A person with a lot of experience and skill in a particular activity.
e.g. She’s an old hand at dealing with the press.
- Behind sb’s back: Without somebody’s knowledge or permission.
e.g. Have you been talking behind my back?
- Go to your head (of success, praise): To feel too proud of yourself in a way that other people find annoying.
e.g. You have changed master, I think power’s gone to your head.
- Be on your/its last legs: To be about to die or to stop functioning very soon; to be very week or in bad conditions.
e.g. I ‘m having a lot of problems with my car lately, I think it’s on its last legs.