一概而论
yī gài ér lùn · HSK 7
to lump different matters together (idiom)
一 one + 概 sweepingly-all + 而 and + 论 judge = judge everything by one standard
概 carries the sense of a sweeping generalization, and 论 is to discuss or pass judgment. Together: 一概而论 means to judge unlike things by a single measure, ignoring their differences.
一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'
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.