学 (xué): To learn, to study, knowledge. The character depicts two hands over a child under a roof, symbolizing the passing of knowledge.
无 (wú): Without, no, not have. A pictograph originally showing a person dancing with sleeves, it later came to mean “not have” or “nothingness.”
止 (zhǐ): To stop, to cease. This character is a simple pictogram of a foot, representing the act of stopping.
境 (jìng): Boundary, border, realm, state. It's composed of 土 (tǔ, earth) on the left and 竟 (jìng, finish/end) on the right, suggesting a final boundary on the land.
When combined, 学 (learning) 无 (has no) 止境 (stopping boundary), the idiom literally means “Learning has no end-boundary.” It paints a vivid picture of knowledge as a vast, limitless ocean or landscape.