have the advantage of someone
know of
unacquaintedly
you-know-who
whatstheirname
scrape acquaintance
withoutcha
whatshisface
whatshisname
behind someone's back
incognito
personless
chance acquaintance
unbeknown
unbeknownst
stranger
namelessly
stigmaless
unacquainted
gossip
know someone from Adam
no-name
snub
cold shoulder
cut
strangerlike
bandy around
nonstranger
by oneself
throw in at the deep end
facelessly
nonacquaintance
slip away
singleton
talk at
anonymously
character
traitorless
backbiting
friendless
generic you
unknowledgeably
semiacquaintance
forgotten
nonvisitor
dip out
close to home
walk-in
whosiewhatsit
faceless