Ghost is one consumed by rage (6)
I believe the answer is:
wraith
'ghost' is the definition.
(synonyms)
'one consumed by rage' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'by' could be 'at' and 'at' is found within the remaining letters.
This explanation may well be incorrect...
'is' acts as a link.
Can you help me to learn more?
(Other definitions for wraith that I've seen before include "Ghostly apparition" , "Ghost, spectral apparition" , "'Ghost, spectre (6)'" , "Presence" , "Making an emotional appeal" .)