Learn layout of the kidneys (5)
I believe the answer is:
renal
'of the kidneys' is the definition.
(renal means relating to the kidneys)
'learn layout' is the wordplay.
'layout' indicates anagramming the letters (an alternative layout of the letters).
'learn' is an anagram of 'RENAL'.
(Other definitions for renal that I've seen before include "Like an organ" , "Referring to organ" , "Concerned with organ" , "using the reins" , "like kidneys" .)