उद्यतायुधधारिभिः ready to fight, रावणबलैः by Ravana's forces, रक्षिता protected, इयं नगरी this city, अन्येन by others, बलात् with force, धर्षयितुम् to attack, न शक्या not posible.

'It is not possible to attack this city by to outsiders as it is protected by the forces of Ravana with their weapons ready(to attack).