Inventive sort decorates Lancastrian houses (5)
I believe the answer is:
tesla
'inventive sort' is the definition.
(I've seen this before)
'decorates lancastrian houses' is the wordplay.
'houses' indicates the answer is hidden within the clue (part of the clue houses the answer).
'TESLA' is hidden within 'decorates lancastrian'.
(Other definitions for tesla that I've seen before include "Californian company specialising in electric cars" , "Inventor" , "Inventive sort" , "SI unit; steal (anag.)" , "Physicist" .)