One has anger about a spirit (6)
I believe the answer is:
wraith
'a spirit' is the definition.
(I've seen this before)
'one has anger' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'anger' could be 'wrath' (synonyms) and 'wrath' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
'about' is the link.
Can you help me to learn more?
(Other definitions for wraith that I've seen before include "looking pale and thin" , "Making an emotional appeal" , "Ghost, spectral apparition" , "'Ghost, spectre (6)'" , "Spook" .)