redoubtable Synonyms

unnerving formidable greatest notable mighty leading indomitable impressive important illustrious horrific horrid potent powerful respected awe-inspiring influential tremendous tough terrific terrible tenacious strong steadfast stalwart horrible horrendous high-stomached dread dominant direful dire determined daunting commanding awful awesome appalling dreadful fearful fearsome gutty grim gruesome great glorious ghastly frightful frightening foremost