Appearance of a ghost about to disappear (6)
I believe the answer is:
aspect
'appearance' is the definition.
(I know that aspect is a type of countenance)
'a ghost about to disappear' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
'about' could be 'c' (abbreviation for circa) and 'c' is found within the answer.
The remaining letters 'spet' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for aspect that I've seen before include "Particular feature or quality" , "Viewpoint, feature to be considered" , "Look; side of building" , "The way something looks" , "Vista, panorama" .)