It's up for debate (5)
(Other definitions for motion that I've seen before include "Flow - proposal" , "inducing nausea in some travellers" , "Proposal for action" , "Proposal for discussion or a vote" , "MP's proposal" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">it's up for debate</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for topic that I've seen before include "Question" , "Content of argument" , "Subject (of a talk, etc)" , "Issue (for discussion)" , "Talking point" .)