おごそかな (translations)→ ceremonious somber
もっともらしい (translations)→ acceptable appropriate authenticity decorously glib plausible presumable resonable
堅い (translations)→ indissoluble promise prude solid straight unshakable
厳かな (translations)→ awesome oracular
重大 (translations)→ big important matter vital
生真面目な (translations)→ overserious serious staid
