hunger

n. desire for food, need for food; feeling of needing to eat; yearning desire, craving

v. need to eat, feel the desire to eat; yearn for, desire

Hunger is a feeling experienced when the glycogen level of the liver falls below a threshold, usually followed by a desire to eat. The usually unpleasant feeling originates in the hypothalamus and is released through receptors in the liver. Although an average nourished human can survive weeks without food intake, the sensation of hunger typically begins after a couple hours without eating and is generally considered quite uncomfortable.
See more at Wikipedia.org...

Hunger /hun·ger/ a craving, as for food. air hunger Kussmaul's respiration. hun·ger n. 1. A strong desire or need for food. 2. [more]Hunger - Community and Resources

Noun
1. a physiological need for food; the consequence of foood deprivation
(synonym) hungriness
(hypernym) drive
(hyponym) bulimia
2. strong desire for something (not food or drink); "a thirst for knowledge"; "hunger for affection"
(synonym) thirst
(hypernym) desire
(derivation) crave, thirst, starve, lust
Verb
1. feel the need to eat
(hypernym) ache, smart, hurt
(derivation) hungriness
2. have a craving, appetite, or great desire for
(synonym) crave, thirst, starve, lust
(hypernym) desire, want
(derivation) thirst
3. be hungry; go without food; "Let's eat--I'm starving!"
(synonym) starve, famish
(hypernym) suffer, hurt
(derivation) hungriness

n. hunger, famine, starvation, desire for food, need for food; feeling of needing to eat