What does boil mean? can it indicate something bad?

Skin infection: This is a collection of purulent infected material under the skin which os roasted hot painful. It may respond to warm compresses, bit large boils need to be drained and packed.

Not usually: A boil is a small (usually) area of infection forming pus in the skin or just under the surface of the skin. Often, hot wet packs will bring it to a head and allow it to drain. Sometimes it may need treatment with antibiotics. It is very seldom that it will represent or become something severe.