causing an emotional disturbance; "his disconcerting habit of greeting friends ferociously and strangers charmingly"- Herb Caen; "an upsetting experience"
so remarkably different or sudden as to cause momentary shock or alarm; "Sydney's startling new Opera House"; "startling news"; "startling earthquake shocks"
inspiring fear; "the formidable prospect of major surgery"; "a tougher and more redoubtable adversary than the heel-clicking, jackbooted fanatic"- G.H.Johnston; "something unnerving and prisonlike about high grey wall"
extremely impressive in strength or excellence; "a formidable opponent"; "the challenge was formidable"; "had a formidable array of compositions to his credit"; "the formidable army of brains at the Prime Minister's disposal"