Place turning up in extremely foolish fixation (6)
I believe the answer is:
fetish
'fixation' is the definition.
(thesaurus)
'place turning up in extremely foolish' is the wordplay.
'place' becomes 'site' ('site' can be a synonym of 'place'**).
'turning up' says the letters should be written in reverse.
'in' is an insertion indicator.
'extremely' means to remove the middle letters.
'foolish' with its centre taken out is 'fh'.
'site' backwards is 'etis'.
'etis' put inside 'fh' is 'FETISH'.
(Other definitions for fetish that I've seen before include "Object worshipped for its supposed power" , "Object worshipped as having a spirit" , "An abnormal object of sexual desire" , "magical object" , "charm" .)