Standing at the bottom, turn round (8)
I believe the answer is:
enduring
'standing' is the definition.
('endure' can be a synonym of 'stand')
'at the bottom turn round' is the wordplay.
'at the bottom' becomes 'end' (I can't justify this - if you can you should believe this answer much more).
'turn' becomes 'u' (a 'U-turn' is a kind of turn).
'round' becomes 'ring' ('ring' can be a synonym of 'round').
'end'+'u'+'ring'='ENDURING'
Can you help me to learn more?
(Other definitions for enduring that I've seen before include "Lasting a very long time, despite hardship (8)" , "Lasting, unceasing" , "having lasting qualities" , "Eternal" , "Long-lasting" .)