FORMIDABLE

adj. 1 alarming, appalling, dreadful, frightful, awesome, awe-inspiring, menacing, horrifying, frightening, intimidating, daunting, petrifying, terrifying A formidable, fire-breathing dragon blocked our exit 2 terrific, fantastic, unbelievable, incredible, impressive, prodigious, mind-boggling, awesome, Colloq mind-blowing, freaky They are a formidable talent and will sell a million records this year 3 arduous, indomitable, overwhelming, staggering, powerful, mighty, difficult, challenging, burdensome, onerous She has formidable obstacles to overcome before becoming a doctor