n. Someone (or something) with thick skin. It is used for animals such as an elephant or a hippopotamus.n. A member of the obsolete taxonomic group Pachydermata, grouping of thick-skinned, hoofed animals such as the rhinoceros, hippopotamus, elephant, pig and horse.n. An elephantn. A person that is not affected by (does not care about) what others say about him or her.n. Someone who is insensitive.