Screen boy up for outrage (7)
I believe the answer is:
scandal
'for outrage' is the definition.
(synonyms)
'screen boy up' is the wordplay.
'screen' becomes 'scan' (I can't explain this - if you can you should believe this answer much more).
'boy' becomes 'lad' (informal term for boy).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'lad' written backwards gives 'dal'.
'scan'+'dal'='SCANDAL'
Can you help me to learn more?
(Other definitions for scandal that I've seen before include "Outrageous event" , "Something shameful or disgraceful, often public" , "something injurious to one's reputation" , "Outraging event" , "Public disgrace" .)