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Hunger is a response to nutritional needs. It can be tied to circadian rhythms, daily timing periods, to just overall volume of food in the system, or very nutrient-specific, causing animals to seek very particular types of foods.
Nutrients include the components of the major biological molecules: carbohydrates, such as sugars, starches, and fibers (absorbed as sugars), used mostly as an energy fuel; proteins (absorbed as amino acids), used in a broad range of ways, including as enzymes; lipids, fats, oils, waxes, and others, usable due mostly to their water-repellent qualities, which makes carriers a necessity to get the components to dissolve in body fluids for transport.
Minerals are used a few ways in animal systems. Ions / salts / electrolytes are used in a number of processes, including the function of nerves and muscles. Minerals are often a critical component of particular protein molecules, such as hemoglobin only being an oxygen carrier with iron atoms embedded in the molecules.
Vitamins are somewhat hard to define, since the "true" definition is very human-centered. Enzyme systems often require small coenzyme molecules to function properly. Most of these coenzyme molecules are made in the cells, but since they are used in many biological systems and are small enough to be absorbed without breakdown, they don't have to be made if enough is present in food. Humans, being omnivores, have a long history of not having to make a long list of coenzymes, and if we once could make them, we have lost that ability (the unused genes have mutated beyond functionality). Vitamins is particularly that list of coenzymes that humans need to obtain from food; different animals with different food histories would have different lists.
Water, although absolutely necessary for the proper workings of all cell chemistry, is not generally considered a nutrient - we don't digest it, we don't really transform it, it's not used the way that other nutrients are.
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