Kapu refers to the ancient Hawaiian code of conduct of laws and regulations. The kapu system was universal in lifestyle, gender roles, politics, religion, etc. An offense that was kapu was often a corporal offense, but also often denoted a threat to spiritual power, or theft of mana. Kapus were strictly enforced. Breaking one, even unintentionally, often meant immediate death,Koʻo kapu. The concept is related to taboo and the tapu or tabu found in other Polynesian cultures. The Hawaiian word kapu is usually translated to English as "forbidden", though it also carries the means of "sacred", "consecrated", or "holy".
As these examples might suggest, the sense of the term in Polynesia carries connotations of sacredness as much as forbidden-ness. Probably the best way to translate kapu into English is as meaning "marked off" or ritually restricted. The opposite of kapu is "noa" meaning "common" or "free".
Most famous are the Kapuhili restrictions placed upon contact with chiefs (kings), but these also apply to all people of known spiritual power. Kapu Kū mamao means prohibited from a place of the chief, while Kapu noho was to assemble before the chief. It was kapu entering a chief's personal area to come in contact with his hair or fingernail clippings, to look directly at him and to be in sight of him with a head higher than his. Wearing red and yellow feathers (a sign of royalty) was kapu, unless you were of the highest rank. Places that are kapu are often symbolized by Pahu Kapu, two crossed staffs, each with a white ball atop.