Disparaging remark about a French count's biggest fear (8)
I believe the answer is:
sunlight
'count's biggest fear' is the definition.
I can't tell whether this defines the answer.
'disparaging remark about a french' is the wordplay.
'disparaging remark' becomes 'slight' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' indicates putting letters inside.
'a french' becomes 'un' ('a' in French).
'slight' placed around 'un' is 'SUNLIGHT'.
Can you help me to learn more?
(Other definitions for sunlight that I've seen before include "Solar radiation" , "Ray" , "port?" , "Possible reason why blinking" , "Hustling under heavenly radiance" .)