proverbial

a. 谚语的,如同谚语的

The conditioned response, once it is firmly established, can be extinguished dozens of times, but it sill always return, like the proverbial bad penny.

条件反射一经形成，虽然可以一次又一次地压制下去，但是它总会重新再现，真是摆也摆不脱扔也扔不掉。

He is the proverbial square peg in a round hole.

他正是谚语中所说的那种方枘圆凿不得其所的人。