Turned on to be turning up in punch-up with dagger (8)
I believe the answer is:
stiletto
'dagger' is the definition.
(I know that stiletto is a type of dagger)
'turned on to be turning up in punch-up' is the wordplay.
'turned on' becomes 'lit' (I've seen this in another clue).
'to be turning up' says the letters should be written backwards.
'in' indicates putting letters inside.
'punch-up' becomes 'setto' (I can't explain this - if you can you should believe this answer much more).
'lit' back-to-front is 'til'.
'til' going into 'setto' is 'STILETTO'.
'with' is the link.
Can you help me to learn more?
(Other definitions for stiletto that I've seen before include "Tapering dagger" , "Thin dagger; heel" , "Dagger with narrow blade, or a high heel" , "Dagger; tapered heel" , "Kind of heel" .)