Quietly sent Lily out (8)
I believe the answer is:
silently
'quietly' is the definition.
(I've seen this before)
'sent lily out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'sent'+'lily'='sentlily'
'sentlily' is an anagram of 'SILENTLY'.
(Other definitions for silently that I've seen before include "Keeping mum" , "Without a word" , "Soundlessly" , "Without making a noise" , "Without a sound" .)