Lukewarm self-assessment? If so, there's no getting over it (10)
I believe the answer is:
impassable
'if so there's no getting over it' is the definition.
(something impassable cannot be travelled over)
I cannot understand how the remainder of the clue works.
(Other definitions for impassable that I've seen before include "Blocked to travel" , "preventing progress" , "won't be crossed" .)