The term 'One With a Thick Skin' can be solved by three different crossword solutions: RHINOCEROS (10 letters), Rhino (5 letters), and HIPPO (5 letters). Rhinoceroses, rhinos, and hippos are all large mammals with thick skin, which is why they are all valid answers to the clue. Rhinoceroses are the largest of the three, and have two horns on their snouts. Rhinos are similar in size to hippos, but have one horn on their snouts. Hippos are the smallest of the three, and are known for their large mouths and teeth.