He saw the hesitation on the man's face and in his gaze, so Gellert remained content to wait without a word; if the man was quick enough in terms of intelligence, perhaps he might pick up on what Gellert was talking about. If nothing else, it implied to the dark wizard that his magic to make him invisible worked a treat.
A chuckle left Gellert's lips, an amused smirk appearing shortly after while he crossed his arms over his chest. So the man had finally began to pick up on Gellert's hints. "Spying, such a strange word. It almost implies scandalous things, which isn't possible seeing as those little meetings you have with Albus Dumbledore are incredibly dull in itself." He pressed a finger against his lips, as if thinking to himself for a moment. "I was observing. That's a much better word. After all, a man of your age learning magic from one who is younger then you is worth observing, even for a small amount of time. Its....curious."
His smirk didn't fade, despite Peter's insistence to learn his name. "I'm almost hurt that you don't know who I am. Surely your teacher would have mentioned me, or perhaps warned you to stay away from me. It seems to be quite the pattern in the village since my arrival."