Beginning to see, except when lacking light (7)
I believe the answer is:
sunless
'lacking light' is the definition.
Both the definition and answer are adjectives. Perhaps you can see a link between them that I don't see?
'beginning to see except' is the wordplay.
'beginning to' suggests taking the first letters.
'except' becomes 'unless' (I've seen this in another clue).
The initial letter of 'see' is 's'.
's'+'unless'='SUNLESS'
'when' is the link.
Can you help me to learn more?
(Other definitions for sunless that I've seen before include "Offering nothing for a tanner" , "Unlit by solar light" , "Clouded over" , "grey" , "Cloudy" .)