In truth, poorly liver close to surgery (6)
I believe the answer is:
verily
'in truth' is the definition.
(I've seen this in another clue)
'poorly liver close to surgery' is the wordplay.
'poorly' is an anagram indicator (a poor spelling).
'close to' says to take the final letters (the close of something is the end).
The final letter of 'surgery' is 'y'.
'liver' anagrammed gives 'veril'.
'veril'+'y'='VERILY'
(Other definitions for verily that I've seen before include "It's livery, in truth" , "Truly (archaic)" .)