What is meaning of the idiom to give someone a hand?

If your hands are tied, then it means you can not do anything about the problem or issue. The concept is that you usually need your hands to do something. If they are tied, you can't do anything.

The idiom means impress someone is egg on

You would say they were "full of themselves" or "blowing their own horn."

The usual implied meaning is that the "someone" that you're going to "have a word with" has done something that you take issue with. Saying you're going to have a word with them means you're going to...

The meaning of the English phrase "to give a hand" to help someone. A variation of this phrase is "to give a helping hand"; this means to assist someone in working towards a common goal.