勤勉
きんべん · kinben · JLPT N1 · na-adj
diligence
🐜 勤 = work or duty + 勉 = striving: together 勤勉 means diligence, industry
Both characters carry the idea of effort. 勤 is work or duty, and 勉 is striving to do better. Stacked, they mean steady, earnest effort, which is why the word also covers industry.