丈二和尚摸不着头脑 - Chinese Idiom

丈二和尚摸不着头脑:

Literally means:

one cannot reach the head of a giant; cannot make head or tail of something

Actually means:

丈二, equals 12 Chi in Chinese measurement, which in turn, equals 4 meters. It refer to a giant's height. 和尚, Buddhist monk.

The whole phrase literally means it is difficult for one of average height to reach the head of a giant. It figuratively means one encounters something confusing and feels at a loss how to figure it out.

丈二等于12尺，即4米，泛指很高；和尚，信佛并出家修行的男人。

丈二和尚摸不着头脑，一丈二尺高的和尚，一般人摸不到他的头。比喻碰到情况不明的事，却又弄不清楚它的原因或底细。