Drunk unable to open house (5)
I believe the answer is:
lotto
'house' is the definition.
(I've seen this before)
'drunk unable to open' is the wordplay.
'drunk' becomes 'blotto' (I've seen this before).
'unable to open' means to remove the first letter.
'blotto' with its first letter taken away is 'LOTTO'.
(Other definitions for lotto that I've seen before include "Children's game similar to bingo" , "Game of chance based on numbered balls being drawn at random" , "Game in which numbers are drawn" , "Game of chance similar to bingo" , "National game with large money prizes" .)