不知所云 (bù zhī suǒ yún) — to not understand what someone is talking about; to be unable to follow someone's point

A drawing of the thing itself, worn down over three thousand years into a few strokes.

The picture in 不 originally showed a flower’s calyx; the “no” sense came later from a related character, not from this picture.

Two or more meaningful parts placed together so that their meanings combine into a new one.

An early form of 知 showed 大 (adult), 口 (mouth), and 子 (child): an adult speaking to a child to pass on knowledge. The 子 part was dropped, and the 大 part changed shape.

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

所 pairs 斤, an axe, with 戶, which gives the sound hù; the old meaning was the sound of logging.

Two or more meaningful parts placed together so that their meanings combine into a new one.

This origin belongs to the traditional form 雲; 云 is its simplified writing.

The traditional form 雲 is 雨 (rain) plus 云; 云 was the original writing for 'cloud', and 雨 was added to separate it from the borrowed sense 'to say'.