Eager for knee operation (4)
I believe the answer is:
keen
'eager' is the definition.
(I've seen this before)
'knee operation' is the wordplay.
'knee' anagrams to 'KEEN'.
But, I am not clear how the anagram is indicated.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for keen that I've seen before include "Having a fine edge to weep over the dead" , "Sharp -- express grief" , "Anxious" , "Avid, enthusiastic" , "Eager, enthusiastic" .)