if people, things or situations are formidable, you feel fear and/or respect for them, because they are impressive or powerful, or because they seem very difficult:
In debate he was a formidable opponent. * Somehow the small but formidable woman fought her way through the crowd to reach her son. * She has a formidable list of qualifications. * The two players together make a formidable combination. * The task was a formidable one. * They had to overcome formidable obstacles.
formidably adverb:
He now has the chance to prove himself in a formidably difficult role. * She's formidably intelligent.
