How NOT to explain the meaning of a phrase

If a person says "I don't understand what they mean by [phrase]" or "What does [phrase] even mean?", replying with the dictionary definition of every word in the phrase is not helpful. (Especially when you include every meaning in the dictionary definitions, not just the one that applies to the phrase in question!)

Apart from the fact that if it were a matter of dictionary definitions they would just google it, if they are missing the meaning of the word they would say "What does [word] mean?" If I said "The Governor General prorogued Parliament" and you didn't know what prorogue meant, you wouldn't say "What does prorogue Parliament mean?", you would say "What does prorogue mean?" If, in some bizarro universe, you knew what the word prorogue means in general terms and you knew what the word Parliament means but you don't know what proroguing Parliament is, THEN you would say "What does prorogue Parliament mean?" You'd want to know the specific implications for Parliament, not the general dictionary definition.

Or, to use a simpler example, if you didn't understand what was meant "Coalition if necessary but not necessarily coalition," looking up all those words wouldn't help. The information you're probably missing here is that it means the Opposition doesn't intend to automatically make the Government fall, but they are prepared to do so if the Government is inadequate - basically using the threat of a coalition to keep the Government in line. That information isn't found in the dictionary definitions; if you don't get it, it's really a political strategy question.

So yeah, posting a definition of every word in a phrase doesn't help people understand the phrase. And worst case, it can make you look like a dickhead. Don't do it.