old: having been around a long time and no longer new, whether worn out, left in the past, or long established
This word means "old" in the sense of something that has existed for a long time and stands over against what is new. It is the natural opposite of the two Greek words for "new": καινός, new in kind or quality, and νέος, new or young in time. The Gospels pair it with both in the picture of old garments and old wineskins that cannot hold what is fresh.
Depending on context the "oldness" can pull in different directions. Sometimes it is simply neutral or even positive: an old commandment is one the readers have had from the start, and aged wine is prized over new. But often the word carries a shadow of "worn out" or "obsolete," something that has had its day and is being set aside: the burst wineskin, the old batch of leaven that must be cleared out, the person's former self, the covenant that is passing.
One thing the word does not do is describe how old a person is. For an elderly or senior person the New Testament uses other words. Nor does it reach back to "ancient" or "original" times; that shade belongs to the near-synonym ἀρχαῖος. Here the accent falls on "former" and "no longer new."