Of the sloping type (6)
I believe the answer is:
italic
'sloping type' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for italic that I've seen before include "leaning over" , "Print style used for emphasis, titles of books, etc" , "Kind of typeface" , "Latin is" , "Printed in a sloping type" .)