αὐτόπτις

From LSJ

τοῦ δὲ πολέμου οἱ καιροὶ οὐ μενετοί → in war, opportunities won't wait | the chances of war will not wait (Thucydides 1.142.2)

Source

Spanish (DGE)

la testigo ocular (θέα) Sch.Er.Il.2.807 (p.172).

Translations