反而
fǎnér · HSK 4
on the contrary
↩️ 反 = reverse/contrary + 而 = yet/but → 'yet contrary' = on the contrary
反 carries the sense of flipping or opposing, and 而 is a classical connector meaning 'yet' or 'but'. Together they flag a reversal of expectation: not what you'd predict, but the opposite instead.
反 — hand 又 under cliff 厂
Originally a pictograph of a hand (又) turning something over against a cliff or slope (厂), depicting the action of flipping or reversing. From this came the core meaning 'to turn over,' which extended to 'opposite,' 'contrary,' and 'rebel against.' The character is purely semantic, with no phonetic component.
而 — pictograph of beard/whiskers hanging from chin
Originally a pictograph of a beard or facial hair hanging below the chin, visible clearly in oracle bone and bronze script forms. The beard meaning was lost early, and the character was borrowed phonetically to write the grammatical conjunction 'and/but/yet'. This connective use has been standard since classical Chinese.