"Nihau" is a Hawaiian greeting that means "hello" or "welcome". While there are no direct synonyms for this word, there are several other words that convey a similar sense of welcoming or greeting. "Aloha" is a Hawaiian word that also means "hello" and is commonly used as a greeting. "Salutations" is a more formal way of saying "hello" and can be used in a business or professional setting. "Greetings" is another formal greeting that can be used in a variety of situations. "Hey" and "hi" are more casual alternatives to "hello". Regardless of which word is used, it's important to greet others with kindness and positivity.