περιοπτέος
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)
English (LSJ)
α, ον, (περιοράω)
A to be overlooked or suffered, c. part., οὔ σφι π. Ἑλλὰς ἀπολλυμένη Hdt.7.168 ; ἡμῖν τοῦτό ἐστι οὐ π., γένος τὸ Εὐρυσθένεος γενέσθαι ἐξίτηλον Id.5.39. 2 to be watched or guarded against, Th.8.48. II περιοπτέον one must overlook or suffer, X. Lac.9.5, Agath.3.10.