逆らう
さからう · sakarau · JLPT N3 · verb-godan
to go against
🐟 逆 = reverse; sakarau sounds like sack a row: rowing against the tide
The kanji 逆 means reverse or backwards, as in 逆 gyaku (opposite). Add the verb ending らう and you get moving in reverse against something. A salmon swimming upstream is the classic case: 流れに逆らう means going against the current.
逆 — 辶 walk + 屰 (inverted 大 person)
逆 combines the walking radical 辶 with 屰, a pictograph of an upside-down person. The original sense was 'to meet, go against the flow,' as if walking toward someone coming the opposite way. From this it extended to mean 'reverse, contrary, disobey.'