As an article, it gets me upset (4)
I believe the answer is:
item
'as an article' is the definition.
I can't judge whether this definition defines the answer.
'it gets me upset' is the wordplay.
'gets' is a charade indicator (letters next to each other).
'upset' says the letters should be written in reverse.
'me' written backwards gives 'em'.
'it'+'em'='ITEM'
Can you help me to learn more?
(Other definitions for item that I've seen before include "Single article on a list" , "Entry (in an account)" , "Piece of news: unit" , "Two people widely seen as one?" , "Two people romantically linked" .)