Cat maybe climbing over usual empty shed (5)
I believe the answer is:
moult
'shed' is the definition.
(I know that shed can be written as moult)
'cat maybe climbing over usual empty' is the wordplay.
'cat maybe' becomes 'tom' (a tom is a male cat. I am not sure about the 'maybe' bit.).
'climbing' is a reversal indicator (in a down clue, letters climb up).
'over' means one lot of letters goes inside another.
'empty' means to remove the middle letters.
'usual' with its centre taken out is 'ul'.
'tom' back-to-front is 'mot'.
'mot' going around 'ul' is 'MOULT'.
Can you help me to learn more?
(Other definitions for moult that I've seen before include "shed down perhaps" , "Periodically cast off hair etc." , "Shed old feathers" , "Of animal, shed hair" , "Shed feathers, fur etc" .)