Ground rent at high level? (8)
I believe the answer is:
crevasse
'ground rent' is the definition.
'crevasse' can be an answer for 'rent' (thesaurus). I'm not sure about the 'ground' bit.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for crevasse that I've seen before include "opening" , "big split" , "Deep glacial fissure" , "climbing hazard in glacier" , "Deep glacial crack" .)