The term 'brannigans' can be used to describe various things, from wild parties and brawls to a raucous and enjoyable time among friends. It's fun, informal and oftentimes impromptu in nature. Nonetheless, there are a few synonyms that can be used in place of 'brannigans' to express the same ideas. For example, you can use terms like 'festivities,' 'celebrations,' 'merrymakings,' 'shenanigans,' 'jollification,' 'revelry,' 'carousal,' 'jubilation,' among others. These synonyms carry similar connotations but are not as common as brannigans. Nevertheless, they are a great way to vary your choice of words and effectively communicate the same message.