Cut off his nitride supply (10)
I believe the answer is:
disinherit
'cut off' is the definition.
(I've seen this in another clue)
'his nitride supply' is the wordplay.
'supply' indicates anagramming the letters (in a supple way).
'his'+'nitride'='hisnitride'
'hisnitride' anagrammed gives 'DISINHERIT'.
(Other definitions for disinherit that I've seen before include "Remove as heir" , "Lanarkshire town" , "Write out of a will" , "Cut off as with a shilling" .)