Stand out or up river guarding hundred and ten (5)
I believe the answer is:
excel
'stand out' is the definition.
(I know that stand out can be written as excel)
'up river guarding hundred and ten' is the wordplay.
'up river' becomes 'eel' (I can't explain this - if you can you should give a lot more credence to this answer).
'guarding' means one lot of letters goes inside another.
'hundred' becomes 'c' (Roman numeral).
'and' is a charade indicator (letters next to each other).
'ten' becomes 'X' (Roman numeral).
'c' put after 'x' is 'xc'.
'eel' going around 'xc' is 'EXCEL'.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for excel that I've seen before include "Do really well as at exams" , "Be pre-eminent" , "Top" , "Perform extremely well" , "surpass all others" .)