Gardner, sailor, or an incarnation (6)
I believe the answer is:
avatar
'an incarnation' is the definition.
(I know that incarnation can be written as avatar)
'gardner sailor' is the wordplay.
'gardner' becomes 'ava' (actress Ava Gardner).
'sailor' becomes 'tar' (slang term for a sailor).
'ava'+'tar'='AVATAR'
'or' acts as a link.
(Other definitions for avatar that I've seen before include "Computer object representing the user" , "Computer icon representing the user" , "A person who seems to embody a particular ideal" , "Hindu manifestation of deity in human form" , "heavenly body!)" .)