His dark deeds needn't be at night (7)
I believe the answer is:
burglar
This might be a double definition.
'his dark deeds needn't' is the first definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'at night' is the second definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'be' acts as a link.
Can you help me to learn more?
(Other definitions for burglar that I've seen before include "Building robber" , "House robber" , "House-violating thief" , "One enters a building in order to steal" , "A criminal on one's premises" .)