rough as a cob means: It’s very unpleasant. The rough, sandpaper-like surface of a corncob was used for wiping one’s backside. (in Community Dictionary, added by Mia Soto)
What else does rough as a cob mean?
- A corncob used to be used for personal hygiene in an earlier era. It was also used as a way of concluding visits to the outside toilet. One can describe themselves as “rough as cobs” by their unpolished approach to communication and actions. (in Community Dictionary, added by Teófanes González)