Wrench spear around with knights (7)
I believe the answer is:
spanner
'wrench' is the definition.
(synonyms)
'spear around with knights' is the wordplay.
'around' indicates anagramming the letters.
'with' indicates putting letters inside.
'knights' becomes 'NN' (the chess abbreviation for knight written twice).
'spear' is an anagram of 'spaer'.
'spaer' enclosing 'nn' is 'SPANNER'.
(Other definitions for spanner that I've seen before include "Tool for fastening nuts" , "Hand tool for nuts" , "Bolt tightener" , "In the works, it's disruptive" , "Tool for tightening or loosening" .)