Point to mine developing the sobriquet (7)
I believe the answer is:
epithet
'sobriquet' is the definition.
(I've seen this before)
'point to mine developing the' is the wordplay.
'point' becomes 'e' (E is an example).
'to mine' becomes 'pit' (down the pit).
'developing' indicates anagramming the letters.
'the' is an anagram of 'het'.
'e'+'pit'+'het'='EPITHET'
(Other definitions for epithet that I've seen before include "qualifier" , "Adjective expressing some quality of a person" , "nickname" , "Fitting description" , "title" .)