The ability to ignore verbal attacks or criticism from others. If you're going to pursue a career in politics, you're going to have to develop a thick skin and not let the criticism of your detractors bother you.
Insensitivity to criticism or insult, as in You can tell him exactly what you think of his new piece; unlike most composers he has a thick skin . This term transfers an impervious outer coating to mental or emotional toughness. [Mid-1500s]