Bottom of knight pinched by my boss (3)
I believe the answer is:
end
'bottom' is the definition.
(I've seen this in other clues)
'knight pinched by my boss' is the wordplay.
'knight' becomes 'N' (chess abbreviation).
'pinched by' is an insertion indicator (inserted letters get pinched or taken).
'my boss' becomes 'ed' (abbreviation for editor, the setter's boss).
'n' going inside 'ed' is 'END'.
'of' is the link.
(Other definitions for end that I've seen before include "Discontinue" , "Finish, close" , "Limit" , "Concluding purpose" , "SECOND PART OF 10" .)