σταυροῦν

From LSJ

φθείρουσιν ἤθη χρήσθ' ὁμιλίαι κακαί → bad company ruins good habits

Source

Greek > English (Woodhouse Verbs Reversed)

(see also: σταυρόω) fortify with a stockade, surround with a palisade

Lexicon Thucydideum

vallis munire, to fortify the rampart, 7.25.7,
PASS. 6.100.1.