Graze from sabre unsheathed when principal spins around (8)
I believe the answer is:
abrasion
'graze from sabre' is the definition.
'abrasion' can be an answer for 'graze' (I've seen this before). I'm not certain of the 'from sabre' bit.
'unsheathed when principal spins around' is the wordplay.
'unsheathed' becomes 'bra' (I can't justify this - if you can you should give a lot more credence to this answer).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'principal' becomes 'no i' (number one).
'spins' shows that the letters should be reversed in order (I've seen 'spun' mean this).
'around' is an insertion indicator.
'noi' written backwards gives 'ion'.
'as'+'ion'='asion'
'bra' put into 'asion' is 'ABRASION'.
Can you help me to learn more?
(Other definitions for abrasion that I've seen before include "A scrape or mark of rubbing" , "Skin wound" , "Cut or scratch" , "Area where the skin is torn" , "Sore mark caused by rubbing" .)