Grudge-holding right little imp (6)
I believe the answer is:
sprite
'imp' is the definition.
(I've seen this before)
'grudge-holding right little' is the wordplay.
'grudge' becomes 'spite' (I've seen this in another clue).
'holding' indicates putting letters inside.
'right' becomes 'rt' (abbreviation as in Rt Hon- the Right Honourable).
'little' means to remove the last letter (the word is not quite complete).
'rt' with its last letter taken off is 'r'.
'spite' going around 'r' is 'SPRITE'.
(Other definitions for sprite that I've seen before include "Goblin, elf or imp" , "Nimble elf-like creature - icon in computer game" , "Dainty type" , "Elf, fairy" , "Small, playful fairy" .)