After eating the last piece of cheese, Derek unfortunately gave off a bad odour (6)
I believe the answer is:
reeked
'off a bad odour' is the definition.
I can't tell whether this defines the answer.
'after eating the last piece of cheese derek unfortunately' is the wordplay.
'after eating' means one lot of letters goes inside another.
'the last piece of' indicates one should take the final letters.
'unfortunately' indicates an anagram.
The last letter of 'cheese' is 'e'.
'derek' with letters rearranged gives 'reekd'.
'e' put into 'reekd' is 'REEKED'.
'gave' is the link.
Can you help me to learn more?
(Other definitions for reeked that I've seen before include "Was foul-smelling" , "Stank" , "Smelled offensively" , "whiffed" , "Smelt strongly" .)