What is the meaning of motion is out of order?

Answer 1

Someone at a meeting has 'made a motion', a proposal, that the group do some specific thing. A motion can be any one of many dozens of possibilities. In this case, the chairperson of the committee (or the parliamentarian, in very formal settings) has determined that according to the rules of order being used for the meeting, that particular motion cannot be made at this time. There may be other motions that first have to be considered, or there may be some other procedural things that have to be accomplished before that motion can be made. So right after the committee member makes the motion by saying, for example, "I move that we adjourn until tomorrow at 10", the Chair says "That motion is out of order. We first must...." Roberts' Rules of Order are commonly and widely used and respected.

As a footnote, when something is called "out of order" by the Chair (and only the Chair can say this if the assembly is civilized) it has nothing whatever to do with the preferences or positions held by any members of the Chair. It isn't used rhetorically or for effect. It has to do with the technical order in which various things have to be accomplished by the committee.