甚至于
shènzhìyū · HSK 7
even
甚 extreme + 至 reach + 于 to = reaching even to an extreme degree
甚 means very/extreme, 至 means to reach or arrive, 于 marks the target point. Together they push a statement to its limit: things go so far that even the extreme case holds true.
至 — arrow 矢 inverted + ground 一
至 is a pictograph showing an arrow (矢) landing point-down on the ground (一), depicting the moment it reaches its target. The original meaning was 'to arrive' or 'to reach,' which extended to 'utmost' or 'extreme' — the point beyond which one cannot go further.
于 — two horizontal strokes 二 + vertical hook 亅
于 originated as a pictograph of breath or sound flowing outward, depicting exhalation through a passage. In oracle bone script it resembled a curved line showing motion or extension. Over time it became a grammatical preposition meaning 'at,' 'in,' or 'to,' losing its original concrete sense.