"Starving" (adj) - dying because of a lack of food. But this can be used in an informal way to mean very hungry.

"Ravenous" (adj) - extremely hungry.

"Famished" (adj) - extremely hungry.

In everyday English, "starving" is more common than "ravenous" and "famished."

• "I'm starving."

• "I'm ravenous."

• "I'm famished."

"Feel peckish."

"Peckish" (adj) - slightly hungry.

• "What're we doing for dinner? I'm starting to feel peckish."

"Hangry" (informal adj) - bad-tempered or irritable as a result of hunger. This is a combination of the words, "hungry" and "angry."

• "Don't talk to me. I'm getting hangry."

"Die of/from hunger" (expression) - synonym of "starving." This can also be used in an informal way to exaggerate one's hunger.

• "Give me food! I'm dying of hunger."

"Munchies" (informal noun) - small light things or snacks to eat, like chips or chocolate.

"The munchies" (informal noun) - a strong desire to eat snacks.

• "Do you have any snacks? I have the munchies."

"Stomach rumbling/growling" (expression) - abdominal sounds due to food, liquids or air moving through your intestines. 

This expression is often used when feelings of hunger are accompanied by abdominal sounds. However, rumbling can sometimes occur after eating.

• "Where's lunch? My stomach is rumbling already."

• "I'm so hungry. People can hear my stomach growling from the other side of the room."

"I'm so hungry, I could eat a horse" (idiom) - a humorous way of saying you are extremely hungry.

There are other variations with "ox," or "a whole elephant." However, "horse" is the only one found in the Cambridge Dictionary.

Please note: "eat a horse" ≠ "eat like a horse"

 

"Eat like a horse" (idiom) - to always eat a lot of food. Although this is a similar phrase, this refer to one's ability to eat a lot, not about being hungry. 

"Hungry as a wolf/bear/lion/goat/hunter..." - very hungry.

These expressions are considered old-fashioned.

"Make somebody's mouth water" (idiom) - when the smell, sight or even the thought of food that makes your mouth water and want to eat it. The verb, "water," refers to the production of saliva.

This expression is typically used to refer to making a person hungry in response to the smell, sight or thought of food.

• "Thinking of my mum's cooking makes my mouth water."

• "My mouth waters every time I think of my mum's cooking."