unerring
adj
not making mistakes or failing or missing the mark; consistently accurate 不犯錯誤的; 萬無一失的; 一貫準確的
his unerring taste in clothes, instinct for a bargain, sense of direction 他那萬無一失的衣物審美觀點、 討價還價的本能、 方向感
He has an unerring knack of saying the wrong thing. 他有個出言必失的本事.
His aim was unerring. 他百發百中.