With guilt, you abandoned puzzle at dusk (8)
I believe the answer is:
twilight
'dusk' is the definition.
(I know that dusk can be written as twilight)
'with guilt you abandoned puzzle' is the wordplay.
'you' becomes 'u' (commonly used in online communication).
'abandoned' suggests deleting specific letters.
'puzzle' indicates an anagram.
'with'+'guilt'='withguilt'
'withguilt' with 'u' removed is 'withgilt'.
'withgilt' anagrammed gives 'TWILIGHT'.
'at' is the link.
(Other definitions for twilight that I've seen before include "Condition of decline" , "Period of gradual decline or obscurity" , "state of decline" , "Declining stage" , "semi-darkness" .)