再発
さいはつ · saihatsu · JLPT N1 · noun
tax return
再 (again) + 発 (launch/fire) = something launched again, so it comes back
さい means again, and はつ (発) means launch or fire, as in 発車 (departure). A relapse is an illness that launches again after it had stopped.
再 — top 一 + 冂 frame + 土-like inner strokes
再 originally depicted a stack of fish or piled objects, suggesting accumulation or repetition. Over time it came to mean 'again' or 'once more,' emphasizing a second occurrence of an action. The modern form is stylized and no longer clearly pictographic.