Boring one (4)
I believe the answer is:
drip
'boring one' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for drip that I've seen before include "Weed - seep" , "Fall in small blobs" , "Fall or let fall in drops" , "Means of intravenous feeding" , "Splash - softie" .)