丁寧
ていねい polite; courteous
Why it means this
丁 (a nail — 'strike firmly') + 寧 (careful, calm) — originally an army's signal drum-and-gong; came to mean doing things carefully and courteously; polite, painstaking (丁寧な仕事; 丁寧語).
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.