Body organ (6)
'body organ' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for liver that I've seen before include "Internal organ" , "Viler (anag.)" , "Detoxifying organ" , "Abdominal organ" , "Bile-secreting gland" .)
(Other definitions for spleen that I've seen before include "Body organ or bad temper" , "Quick temper - body organ" , "The organ once thought to be the seat of anger" , "Abdominal organ - bad temper" , "Organ causing bad temper?" .)