Nocturnal type beginning to have soak (4)
I believe the answer is:
bath
'soak' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'nocturnal type beginning to have' is the wordplay.
'nocturnal type' becomes 'bat' (I can't justify this - if you can you should give a lot more credence to this answer).
'beginning to' indicates taking the first letters.
The first letter of 'have' is 'h'.
'bat'+'h'='BATH'
Can you help me to learn more?
(Other definitions for bath that I've seen before include "Somerset spa" , "on the Kennet and Avon canal" , "English spa founded by the Romans" , "Sit in it to wash" , "Avon city - tub" .)