Antonyms for young
all:
old.
immature:
sophisticated,
healthy,
old,
experienced,
mature, adult,
older.
noun:
tottery,
centenarian,
decrepit,
late,
Experient,
long-lived,
grown up,
nonagenarian,
mellow,
golden,
later,
white-haired,
spavined.
animate beings that are not mature:
parent.