勤快
qín kuài · HSK 7
diligent
🐜 勤 diligent + 快 quick = quick to put in hard work, never idle
勤 carries the sense of industrious effort; 快 means fast or quick. Together they label someone who is quick to get busy and keeps at it. The ant 🐜 is the stock symbol of this nonstop, hardworking nature.
快 — heart radical 忄 + 夬 (phonetic)
快 is a semantic-phonetic compound. The heart radical 忄 carries the meaning, since the original sense referred to a feeling of pleasure or delight. The right side 夬 supplies the sound. The meaning later extended from 'pleased' to 'quick, fast', the dominant modern sense.