Letters in sloping type (7)
I believe the answer is:
italics
'letters in sloping type' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for italics that I've seen before include "They emphasise" , "Letters in sloping type" , "Sloping font" , "Cursive script" , "Typeface with letters slanting to the right" .)