Haggard equestrian? (5)
I believe the answer is:
rider
This clue is a double definition.
'haggard' is the first definition.
(novelist H Rider Haggard)
'equestrian?' is the second definition.
(equestrian is a kind of rider)
(Other definitions for rider that I've seen before include "Jury's added comment" , "Traveller on horseback" , "One on a horse or cycle" , "Contractual clause" , "Extra provision" .)