it is used to describe something/ someone which is so vulgar that it is intolerable
Definitions (粵典–words.hk)
語句
太過俗氣,令人難以接受 very poor taste; vulgar
陳生開口埋口都係錢,一啲內涵都冇,俗不可耐。
陈生开口埋口都系钱,一啲内涵都冇,俗不可耐。
can4 saang1 hoi1 hau2 maai4 hau2 dou1 hai6 cin2, jat1 di1 noi6 haam4 dou1 mou5, zuk6 bat1 ho2 noi6. All Mr. Chan talks about is money; he has no self-restraint. It's insufferable!