Slow ice climb, scrambling across cliff's centre (9)
I believe the answer is:
imbecilic
'slow' is the definition.
Both the answer and definition are adjectives. Maybe you can see an association between them that I can't see?
'ice climb scrambling across cliff's centre' is the wordplay.
'scrambling' is an anagram indicator.
'across' is an insertion indicator.
'centre' says to take the centre.
The middle of 'cliff' is 'i'.
'ice'+'climb'='iceclimb'
'iceclimb' is an anagram of 'imbecilc'.
'imbecilc' enclosing 'i' is 'IMBECILIC'.
Can you help me to learn more?
(Another definition for imbecilic that I've seen is " stupid".)