Wasteful convent initially failing to collect tax by first of April (11)
I believe the answer is:
unnecessary
'wasteful' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'convent initially failing to collect tax by first of april' is the wordplay.
'convent' becomes 'nunnery' (nunnery is a kind of convent).
'initially failing' means to remove the first letter.
'to collect' indicates putting letters inside (inserted letters are collected by others).
'tax by' becomes 'cess' (I've seen this in another clue. I am not sure about the 'by' bit.).
'first of april' becomes 'a' (cst letter of 'april').
'nunnery' with its first letter taken away is 'unnery'.
'cess'+'a'='cessa'
'unnery' going around 'cessa' is 'UNNECESSARY'.
Can you help me to learn more?
(Other definitions for unnecessary that I've seen before include "Uncalled-for" , "Inessential" , "Needless" , "Not needed" , "excessive" .)