plainness(the condition of being plain) noun [UK: ˈpleɪn nəs] [US: ˈpleɪn nəs]
simplicity [simplicities](quality or state of being simple, unmixed, or uncompounded; as, the simplicity of metals or of earths) noun [UK: sɪm.ˈplɪ.sɪ.ti] [US: ˌsɪm.ˈplɪ.sə.ti]