1.) A derisive term for cheap knockoff versions of real, high-end tactical firearm accessories such as red dot sights, holosights, flashlights, lasers and scopes. Such accessories are highly popular with Airsoft players, since they look cool, cost much less and don't need to be reliable enough for them to actually stake their lives on. A few morons put them on real guns though, which usually results in the cheaply made devices being destroyed by recoil.
2.) A derisive term for the use of an excessive quantity of tactical firearm accessories whether they are real or not.
1a.) The Airsoft player bought a fake EOTech holosight to make his airsoft gun look tacticool. He tried putting it on a real AK-47 later, and the recoil shattered the lens.
1b.) My Aimpoint Comp M2 isn't tacticool. It's the exact same red dot sight as the U.S. Army uses, and can survive an incredible amount of abuse.
2.) The three lasers, four flashlights, scope and two red dot sights on the AR-15 were very tacticool. A real soldier wouldn't put half that much crap on his rifle even if he could.