Messy person's extremely small cooker (6)
I believe the answer is:
sloven
'messy person's extremely small cooker' is the definition.
I can't tell whether this defines the answer.
'extremely small cooker' is the wordplay.
'extremely' means to remove the middle letters (only the extremes of the word are used).
'cooker' becomes 'oven' (synonyms).
'small' with its middle removed is 'sl'.
'sl'+'oven'='SLOVEN'
Can you help me to learn more?
(Other definitions for sloven that I've seen before include "Habitually negligent person" , "slattern" , "scruffy individual" , "Untidy or careless person" , "scruffy sort" .)