Icon sporting a cravat? Not initially (6)
I believe the answer is:
avatar
'icon' is the definition.
(an online icon or image)
'sporting a cravat? not initially' is the wordplay.
'sporting' indicates anagramming the letters.
'not initially' means to remove the first letter.
'cravat' with its first letter taken off is 'ravat'.
'a'+'ravat'='aravat'
'aravat' is an anagram of 'AVATAR'.
(Other definitions for avatar that I've seen before include "Computer object representing the user" , "New embodiment of a familiar idea" , "Human or animal manifestation of Vishnu" , "Bodily form of (Hindu) deity" , "Cyberspace representation of a person" .)