Why the senora's upset? (6)
I believe the answer is:
reason
'why' is the definition.
(thesaurus)
'the senora's upset?' is the wordplay.
'upset?' indicates anagramming the letters (I've seen 'upsets' mean this).
'senora' is an anagram of 'REASON'.
(Other definitions for reason that I've seen before include "Defence" , "Explanation; logic" , "Mental power to justify an act" , "Justification; sanity" , "Justification needed" .)