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