What is the history of the character “耻”?
戰國・楚簡緇衣.28郭店楚簡篆心部說文解字東漢隸樊敏碑　今楷　

「恥」 (Baxter-Sagart OC: /*n̥rəʔ/, humiliation/shame) is comprised of semantic 「心」 (heart, mind) and phonetic 「耳」 (/*C.nəʔ/).

During times when clerical script was in active use, the 「心」 portion of the character was sometimes corrupted into an additional sound hint 「止」 (/*təʔ/). This produces the variant 「耻」, which is the target of PRC's standardisation scheme.

東漢隸樊敏碑　東漢隸孔宙碑　東漢隸池陽令　今楷