'Bashment' is Jamaican Patois for a big party or dance event, especially one with sound systems playing dancehall and reggae music. It can also describe the dancehall music style itself. In British and Caribbean youth speech, 'going to a bashment' means going to a lively dancehall party. The word has no negative or hidden meaning; it is celebratory. If your teen mentions a bashment, they are talking about a music event or party. Worth knowing it can be quite late, loud and adult in atmosphere — appropriate questions about the venue and supervision apply as with any party.