Of course Tonks knew what he meant. She was just hoping that he knew what he meant. It wasn't like he could know, right? And if he didn't know, he'd be confused by her taking color requests. And he didn't look confused, just annoyed that she was taking so long. Well, too bad for him. She had to make sure he wasn't an impostor.
When he made his request, Tonks made quick work of her hair color, turning it a dreadful, unmatching teal with purple zigzags at random intervals. "Is that satisfactory, or would you like to see the polka dots too?"