Least inclined to work - about the end of April, that is (6)
I believe the answer is:
idlest
'least inclined to work' is the definition.
I can't judge whether this definition defines the answer.
'about the end of april that is' is the wordplay.
'about' indicates putting letters inside.
'the end of' indicates one should take the final letters.
'that is' becomes 'id est' ('that is' in Latin).
The last letter of 'april' is 'l'.
'l' inserted within 'idest' is 'IDLEST'.
Can you help me to learn more?
(Other definitions for idlest that I've seen before include "Least diligent" , "most unused" , "Most useless" , "least fond of Labour?" , "Most lazy" .)