Guardsman re-reading novel (9)
I believe the answer is:
grenadier
'guardsman' is the definition.
(French soldier)
're-reading novel' is the wordplay.
're-reading' becomes 'rereading' ('reread' can be a synonym of 're-read').
'novel' indicates anagramming the letters.
'rereading' anagrammed gives 'GRENADIER'.
(Other definitions for grenadier that I've seen before include "guard" , "Soldier; fish; bird" , "A household infantryman" , "African flier" , "Soldier - in red gear (anag)" .)