Object of phobia? (5)
I believe the answer is:
thing
I believe this clue is a double definition.
'object' is the first definition.
'phobia?' is the second definition.
(having 'a thing about' something is fearing it)
'of' acts as a link.
(Other definitions for thing that I've seen before include "Body" , "Obsession" , "Individual unit" , "Inanimate object" , "Object, artefact" .)