Study an article in red (4)
I believe the answer is:
read
'study' is the definition.
(I know that study can be written as read)
'an article in red' is the wordplay.
'an article' becomes 'a' (English indefinite article).
'in' indicates putting letters inside.
'a' placed inside 'red' is 'READ'.
(Other definitions for read that I've seen before include "Study (for a degree?)" , "Interpret printed matter" , "Looked at and understood" , "Studied" , "Perused" .)