Haunt with unnatural sobs describing evacuated entrails (6)
I believe the answer is:
obsess
'haunt' is the definition.
(to haunt can mean to cause an obsession)
'unnatural sobs describing evacuated entrails' is the wordplay.
'unnatural' indicates anagramming the letters.
'describing' is an insertion indicator (describe can mean to form the outline of).
'evacuated' says to hollow out the word (remove centre letters).
'entrails' with its middle taken out is 'es'.
'sobs' anagrammed gives 'obss'.
'obss' enclosing 'es' is 'OBSESS'.
'with' is the link.
(Other definitions for obsess that I've seen before include "Persistently preoccupy" , "Constantly worry (about something)" , "Haunt - preoccupy" , "Control" , "Be constantly talking about" .)