Tolerate a small stream (5)
I believe the answer is:
brook
I believe this clue is a double definition.
'tolerate' is the first definition.
(synonyms)
'a small stream' is the second definition.
(I've seen this before)
(Other definitions for brook that I've seen before include "Stand for" , "Stream; put up with" , "Bear - small stream" , "running water" , "Small fresh-water stream" .)