Overheating
2 Answers
Without detailed information you're asking people to guess. Could be a bad thermostat, radiator cap, radiator, water pump, non working cooling fan, or engine temp sensor, or worst case scenario, blown head gasket. Take it to a shop, they should be able to diagnose the problem fairly quick and get you a repair quote.
As KenF said, Overheating can be caused by several issues. Low on coolant, leaks (internal or external), clogged radiator, bad thermostat, cooling fans not running, etc.