Kept near tide that's turning (8)
I believe the answer is:
retained
'kept' is the definition.
('retain' can be a synonym of 'keep')
'near tide that's turning' is the wordplay.
'that's turning' indicates anagramming the letters.
'near'+'tide'='neartide'
'neartide' with letters rearranged gives 'RETAINED'.
(Other definitions for retained that I've seen before include "Continued to hold on to something" , "Kept" .)