Not to mention the claw, in general sheathed (3,5)
I believe the answer is:
let alone
'not to mention' is the definition.
(synonyms)
'in general sheathed' is the wordplay.
'in' is an insertion indicator.
'general' becomes 'lee' (Robert E. Lee - US revolutionary commander).
'sheathed' becomes 'talon' (I can't justify this - if you can you should believe this answer much more).
'lee' going around 'talon' is 'LET-ALONE'.
'the claw' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for let alone that I've seen before include "Don't touch" , "Don't bother someone - allow to be solitary" , "Not to mention (thing)" , "Not to mention - much less - avoid" , "Not to mention, never mind" .)