experienced
experient
Father Time
Methuselah
Nestor
Old Paar
blase
campaigner
centenarian
cosmopolitan
cosmopolite
dotard
elder
expert
gaffer
geezer
golden-ager
gramps
grandfather
grandsire
graybeard
knowing
master
mature
matured
nonagenarian
not born yesterday
octogenarian
old
old campaigner
old chap
old codger
old dog
old duffer
old geezer
old gent
old gentleman
old hand
old man
old party
old pro
old salt
old sea dog
old soldier
old-time
old-timer
older
oldster
pantaloon
past master
patriarch
man
military man
military personnel
serviceman
American
amateur
assistant
chief
civilian
fellow
fighter
infantry
professional
resident
senior
soldier
volunteer
warrior
would-be