suicide vestnoun [ C ]
uk/ˈsuː.ɪ.saɪd ˌvest//ˈsuː.ɪ.saɪd ˌvest/also bomb vest, /ˈbɒm ˌvest//ˈbɑːm ˌvest/a piece of clothing worn on the upper body with a bomb or bombs attached to it, used to cause an explosion that will kill the person wearing it as well as others:
They foiled an attack by a terrorist wearing a suicide vest.