The word hawk has several meanings:

1. A bird of prey with sharp talons, excellent eyesight, and a hooked beak designed for tearing meat. Hawks hunt smaller animals like mice, rabbits, and other birds. They soar high in the sky, using their incredible vision to spot prey from hundreds of feet up. Red-tailed hawks are common across North America. You might see one perched on a fence post beside a highway, scanning the fields below. Unlike eagles, which are much larger, hawks are medium-sized hunters built for speed and agility.
2. To sell something aggressively or persistently, often in public places. Street vendors hawk their goods by calling out to passersby: “Fresh flowers! Get your fresh flowers here!” The word suggests pushy selling, not the quiet display you'd see in a regular store. Someone hawking magazines or concert tickets is trying hard to catch your attention and make a sale.

When you remember that hawks are focused hunters that chase their prey with determination, it's easier to see why we use the same word for aggressive selling.