List composed by crazy mountaineer (11)
I believe the answer is:
enumeration
'list' is the definition.
(I know that enumeration is a type of list)
'crazy mountaineer' is the wordplay.
'crazy' indicates an anagram.
'mountaineer' is an anagram of 'ENUMERATION'.
'composed by' acts as a link.
(Other definitions for enumeration that I've seen before include "The act of numbering" , "Act of counting" , "Counting process" , "The act of mentioning one by one" .)