Halloa is a greeting used to draw attention or to express surprise. In the English language, there are several synonyms for this word that can be used interchangeably depending on the context. Some common alternatives to the word halloa are hello, hi, hey, yo, and greetings. These words are typically used in informal settings, such as among friends or acquaintances. In more formal settings, an alternative word for halloa might be welcome or good morning/afternoon/evening. Overall, there is no shortage of synonyms for the word halloa, ensuring that individuals can use various greetings depending on the situation or their personal preference.