This morning, for the umpty squillionth time, I have seen this combination of words in print, where it has presumably been written by professional writers/journalists and then passed the scrutiny of professional editors, and not just in print but in the online version of what used to be one of the country's best newspapers:
They mean "peek", which is a quick, often surreptitious look at something. A peak is the usually slightly pointy top of a mound. Mountains have them, as do meringues and nipples.
You might get a sneak peek at a peak in a wardrobe malfunction situation, or into the briefly opened oven door, or through the swirling mist. But it's not an excusable mistake from anyone who's paid to write words and/or check them. It Just. Is. Not.