Dull socks unwrapped by digger (7)
I believe the answer is:
mattock
'digger' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'dull socks unwrapped by' is the wordplay.
'dull' becomes 'matt' (similar in meaning).
'unwrapped' indicates the central letters (the letters which wrap the word are removed).
'by' is a charade indicator (letters next to each other).
The central letters of 'socks' are 'ock'.
'matt'+'ock'='MATTOCK'
Can you help me to learn more?
(Other definitions for mattock that I've seen before include "Pickaxe with one flattened end" , "it may be groundbreaking" , "Pickaxe-like tool" , "Pick" .)