* Εσωτερική δύναμη (Esoteriki dynámi): This is a literal translation, meaning "inner power." It's straightforward and generally understood.
* Ψυχική δύναμη (Psychiki dynámi): This translates to "mental strength" or "strength of soul." It emphasizes the psychological aspect of inner strength.
* Θάρρος (Thárros): This means "courage" or "bravery." While not a direct translation, it often implies inner strength and resilience.
* Αντοχή (Antochí): This means "endurance" or "resistance." It highlights the aspect of inner strength that allows someone to persevere through difficulty.
* Σθένος (Sthénos): This word implies strength, vigor, and might. While not explicitly "inner," it can be used to describe the inner strength that manifests outwardly.
The best choice will depend on the context. If you can provide more context about how you intend to use the phrase, I can help you choose the most appropriate translation.