立て替える
たてかえる · tatekaeru · JLPT N1 · verb-ichidan
to pay for another
💴 立て (put forward) + 替える (replace): you put up the money now, and it gets replaced later
立てる means to put forward or set up, and 替える means to replace or swap. So you put your own money forward first, and the payment is later swapped back to you by the person who owes it.
立 — person standing on ground (大 over 一)
Pictograph of a person standing with arms outstretched on the ground line below. The original oracle bone form clearly shows a frontal human figure planted on the earth. The core meaning 'to stand' extended to 'establish, set up, erect.'
替 — two 夫 (man) over 曰 (say)
Originally written with two 立 (stand) over 白, depicting two people side by side, suggesting replacement or alternation. The form evolved to two 夫 over 曰. The core meaning shifted from 'decline/abolish' to 'replace, substitute for'.