It overshadows things when noisy characters interrupt Lewis (6)
I believe the answer is:
clouds
'characters interrupt lewis' is the definition.
I can't judge whether this definition defines the answer.
'it overshadows things when noisy' is the wordplay.
I cannot really understand how this works, but
'noisy' could be 'loud' (associated in meaning) and 'loud' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for clouds that I've seen before include "Cumulus and stratus, say" , "obfuscates" , "Masses of condensed vapour floating high above" , "work by 3 [FRAYN] ?" , "becomes opaque" .)