Naughty tot kept in pen in small house (7)
I believe the answer is:
cottage
'small house' is the definition.
(I've seen this before)
'naughty tot kept in pen' is the wordplay.
'naughty' is an anagram indicator.
'kept in' means one lot of letters goes inside another.
'pen' becomes 'cage' (I've seen this before).
'tot' with letters rearranged gives 'ott'.
'ott' placed within 'cage' is 'COTTAGE'.
'in' acts as a link.
(Other definitions for cottage that I've seen before include "Rural house" , "building" , "Small single-storey dwelling" , "To make a home" , "Rural dwelling" .)