可想而知
kě xiǎng ér zhī · HSK 7
as one can well imagine...
💡 可 can + 想 think + 而 and + 知 know: you can think it through and know, so it is obvious
Four characters chain literally as can-think-and-know. Once you can think it over, the answer follows on its own, which is why it means the conclusion is obvious or as anyone would expect.
可 — mouth 口 + breath marker 丁 (modified)
可 originally depicted a mouth (口) with a curved stroke suggesting exhaled breath or speech, conveying approval or assent. From this came the meaning 'to permit' or 'can,' as granting permission was expressed verbally. Today it broadly means 'may,' 'can,' or 'approve.'
想 — heart 心 + 相 (xiāng, phonetic)
想 is a semantic-phonetic compound. The heart radical 心 at the bottom carries the meaning, since classical Chinese located thought and feeling in the heart. The top component 相 (xiāng) supplies the sound, and over time the character settled into the senses 'to think,' 'to want,' and 'to miss.'
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.