If you describe something as unmistakable, you mean that it is so obvious that it cannot be mistaken for anything else.
例句
He didn't give his name, but the voice was unmistakable.他沒留下姓名，但是那個聲音是絕不會錯的。...the unmistakable smell of marijuana drifted down.大麻的氣味飄了下來，肯定不會弄錯的
英漢詞典釋義
adj.
顯而易見的,不會弄錯的,不會誤解的
detecting the unmistakable whiff of electoral blackmail發現選舉訛詐的蛛絲馬跡His work bears the unmistakable stamp of genius.他的作品清清楚楚顯示出他的天才。He tried to conceal his distress, but the tremor in his voice was unmistakable.他盡力隱藏悲痛，但是顫抖的聲音卻無疑表明了一切。