Flows out, as the tide
I believe the answer is:
ebbs
'flows out as the tide' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ebbs that I've seen before include "Wanes" , "Goes out like tide" , "Flows back - declines" , "Flows back or recedes" , "fades away" .)