労 (Kanji for labor)

Onyomi

ROU	The boss treats the laborers like ROBOTS

In Japan you can see strong construction work punks with mohawks.

労働(ろうどう)	manual labor ★★★★☆ 労 (labor) + 働 (to do your job) = 労働 (manual labor)
苦労(くろう)	hardships ★★★☆☆ 苦 (suffer) + 労 (labor) = 苦労 (hardships)
労働者(ろうどうしゃ)	laborer ★★☆☆☆ 労働 (manual labor) + 者 (professional) = 労働者 (laborer) laborer. proletarian
過労死(かろうし)	death from overwork ★★☆☆☆ 過 (surpass / too much) + 労 (labor) + 死 (death) = 過労死 (death from overwork)

Labor requires STRENGTH,

such as the glory of chopping down a TREE.

Your raise your HAND to cite your answer: "Teacher! I know!!"