Πεινάω πολύ (Peináo polí)
* Πεινάω (Peináo): I am hungry
* πολύ (polí): very
You could also use είμαι πολύ πεινασμένος/η (eímai polí peinasmenos/i) which is a more literal translation meaning "I am very hungry (masculine/feminine)". However, Πεινάω πολύ is more commonly used in everyday speech.