Really stand out (3)
I believe the answer is:
pop
'really stand out' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pop that I've seen before include "Modern music for the masses" , "Music with mass appeal" , "Palindrome of music for the young" , "Cartoon sailor (showing amazement?)" , "Thus goes the weasel in song" .)