1. A person who is not sensitive to criticism, ridicule, etc.
2. Any of the thick-skinned, nonruminant ungulates, as the elephant, hippopotamus, and rhinoceros.
3. An elephant.
She shrunk down into her oversized sweatshirt, feeling her chest break out in hives, when she realized he called her a big-trunked pachyderm not because of her pluckiness, her brazen habit to talking over their English teacher; he was, in fact, practicing his SAT words by calling her an elephant with a wide butt.