Held up in hag-ridden woods (5)
I believe the answer is:
owned
'held' is the definition.
(thesaurus)
'up in hag-ridden woods' is the wordplay.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'in' indicates the answer is hidden within the clue.
'denwo' can be found hidden inside 'hag ridden woods'.
'denwo' in reverse letter order is 'OWNED'.
(Other definitions for owned that I've seen before include "fully paid off?" , "Acknowledged" , "admitted making confession" , "Possesed" , "Possessed; admitted" .)