Anyone knows what camouflage is, but fewer people have seen a ghillie suit. And unless you are looking very carefully, you may not see it period. Landlords would hire guys to go around their property and repel illegal hunters in the beginnings of the ghillie suit. They were called ghillies and would make suits from old rags and frayed textiles to hide themselves in the brush and wait for poachers.
Today a variety of operations, from combat sharpshooting to paintballing are performed in the ghillie suit. The technology remains the same even though the textiles have changed over time. The modern ghillie suit wearer looks like a pile of sticks when they are being still and can remain undetected even when the opposition or target comes within a very close range to them.