A ghost left a letter with Virginia (5)
I believe the answer is:
larva
'a ghost' is the definition.
(thesaurus)
'left a letter with virginia' is the wordplay.
'left' becomes 'l' (common abbreviation).
'letter' becomes 'r' ().
'with' is a charade indicator (letters next to each other).
'virginia' becomes 'va' (US state abbreviation).
'l'+'a'+'r'+'va'='LARVA'
(Other definitions for larva that I've seen before include "Immature stage of an insect" , "Immature form of an insect before metamorphosis" , "Wriggler" , "Insect's immature form" , "Immature life form" .)