Sick greeting left by husband (6)
I believe the answer is:
ailing
'sick' is the definition.
(similar in meaning)
'greeting left by husband' is the wordplay.
'greeting' becomes 'hailing' (hailing is a kind of greeting).
'left by' is a deletion indicator (word is left or abandoned by specified letters ).
'husband' becomes 'h'.
'hailing' with 'h' taken out is 'AILING'.
(Other definitions for ailing that I've seen before include "Ill" , "In poor health" , "Sickly, poorly" , "Suffering" , "Unwell, in poor condition" .)