expletive [expletives](word added to fill a syntactic position) noun [UK: ɪk.ˈspliː.tɪv] [US: ˈek.splə.tɪv]
parenthesis [parentheses](a clause, phrase or word inserted into a passage which is already grammatically complete) noun [UK: pə.ˈren.θə.sɪs] [US: pə.ˈren.θə.ˌsɪs]