Perplex with a minus sign? (7)
I believe the answer is:
nonplus
'perplex' is the definition.
(synonyms)
'with a minus sign?' is the wordplay.
'with' means one lot of letters go next to another.
'a minus' becomes 'non' (I can't explain this - if you can you should believe this answer much more).
'sign?' becomes 'plus' (plus sign is a kind of sign).
'non' next to 'plus' is 'NONPLUS'.
Can you help me to learn more?
(Other definitions for nonplus that I've seen before include "Dumbfound" , "Utterly confuse" , "Throw into confusion" , "Floor" , "disadvantageous or neutral, presumably" .)