Type type (5)
(Other definitions for sans serif that I've seen before include "Plain style of type" , "Style of typeface" , "Plain typeface" , "plain type of face" , "Style of font" .)
'type type' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for roman that I've seen before include "eg Julius Caesar" , "eg Brutus" , "Ancient Italian" , "Printing style" , "Sort of face" .)