Picture two runners side by side. Outrun is the moment one of them pulls ahead and the gap starts to open — not just moving fast, but moving fast enough to leave the other one behind. English builds a whole row of verbs this way with out-: outrun, outplay, outsell. The part after out- names what you are being compared on.
From the word’s history
The source traces the word simply to out- + run. It does not gloss the prefix, so the reading of out- as beating the other side on that activity is offered as a model built from the pattern (outplay, outsell), not as a translation from the source.
來源資料只把這個字拆成 out- 加 run，沒有替 out- 下定義。所以「out- = 在這件事上贏過對方」是從 outplay、outsell 這一排字歸納出來的看法，是一個好用的想法，不是資料上寫的字義。
packet etymology_text, Wiktionary source_ref kaikki:3f6f69a190036ae4:194921029 (From out- + run.)
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