另當別論 : 另, 別 superfluous? What does 當 add? ABC Chinese–English Comprehensive Dictionary (2003), p 561. I can't access the &quot;slightly revised through July 2005&quot; ed. I also quote Wiktionary.



Why both 另 and 別? Aren't they redundant? They both mean &quot;other&quot;. If you had to pick one, which you pick?

What  does 當 contribute? What changes semantically, if we omit it?
另 (adv) 當 (v) 別 (adj) 論 (n)
另當別論 =  treat separately as a different issue = (it is an exception)
Example:
雖然只有工作人員可以進入後台，但有VIP通行證的客人另當別論 - Although only staff can enter the backstage, people with a VIP pass is an exception