Drain unblocker (7)
I believe the answer is:
plunger
'drain unblocker' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for plunger that I've seen before include "Drain unblocker" , "Sink-unblocker" , "Sink unblocker" , "Device for unblocking drains" , "Rubber pipe unblocker" .)