First Minister tense, doctor admits (8)
I believe the answer is:
Here is my best explanation:
'first minister' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'tense doctor admits' is the wordplay.
'tense' becomes 't' (abbreviation used in many dictionaries).
'doctor' becomes 'surgeon' (surgeon is a kind of doctor).
'admits' is an insertion indicator.
't' placed inside 'surgeon' is 'STURGEON'.
(Other definitions for sturgeon that I've seen before include "Caviar-producing fish", "Source of caviar", "Something fishy here", "Our gents caught a large fish", "The fish that yields caviare", "Caviare-producing fish", "Fish that yields caviare", "Large fish, valued for its roe", "Source of caviare and isinglass" and "Caviar supplier".)