Operator understood dice (8)
I believe the answer is:
sawbones
'operator' is the definition.
(I've seen this before)
'understood dice' is the wordplay.
'understood' becomes 'saw' ('see' can be a synonym of 'understand').
'dice' becomes 'bones' (I've seen this in another clue).
'saw'+'bones'='SAWBONES'
(Other definitions for sawbones that I've seen before include "Surgeon or doctor (slang)" , "A slang surgeon, sounds grating" , "operator" , "Surgeon (joc.)" .)