Enthused about need to leave it closed (4)
I believe the answer is:
shut
'closed' is the definition.
(I know that closed can be written as shut)
'enthused about need to leave it' is the wordplay.
I cannot quite understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
The remaining letters 'shu' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for shut that I've seen before include "not accepting visitors" , "Closed" , "Slam" , "Draw to" , "Out of business" .)