1. watch someone close enough to cause them discomfort
I don't want someone breathing down my neck
The idiom 'to breathe down someone's neck' has a number of potential meanings; 1. To monitor someone closely in an uncomfortable way: "I like the role I'm in but my supervisor is always breathing down my neck. I'm terrified to make a mistake." 2. To be physically close to someone in a way that crosses their personal boundaries or is uncomfortable: "I had to move away from Frank. He was breathing down my neck." 3. To pursue someone intently in a predatory way: "The committee was following his every move and breathing down his neck in the hope that he would slip up and make a mistake." This idiom can be used in social and professional situations to describe feeling uncomfortable due to the behaviour of someone else.