Close up of Jock’s middle daughter in this? (7)
I believe the answer is:
occlude
'close up' is the definition.
(thesaurus)
'jock's middle daughter in this?' is the wordplay.
'middle' means to look at the middle letters.
'daughter' becomes 'd' (genealogical abbreviation).
'in' is an insertion indicator.
'this?' becomes 'clue' (the clue referring to itself!).
The central letters of 'jock' are 'oc'.
'd' placed into 'clue' is 'clude'.
'oc'+'clude'='OCCLUDE'
'of' is the link.
(Other definitions for occlude that I've seen before include "Cut or shut off" , "Stop up, obstruct" , "Cod clue to shut out" , "Block, obstruct" , "Close up, obstruct" .)