conspicuous
Very easy to see because it stands out a lot.
Conspicuous means extremely noticeable or obvious, standing out in a way that's impossible to miss. When something is conspicuous, it draws attention to itself, like a bright red backpack in a sea of black ones, or the only student wearing a costume on a regular school day.
The word often describes things that stand out when they probably shouldn't. A conspicuous stain on your shirt announces itself to everyone who looks at you. A conspicuous absence means someone's missing and everyone notices, like when the class clown is absent and the room feels strangely quiet.
Sometimes people try to be conspicuous on purpose, like wearing flashy clothes to get noticed. But just as often, someone feels conspicuously out of place, like being the new kid walking into a cafeteria where everyone already has their friend groups.
The opposite of conspicuous is inconspicuous, meaning barely noticeable or able to blend in. A spy needs to be inconspicuous, while a lighthouse needs to be conspicuous. Understanding which situations call for standing out versus blending in is part of reading social situations well.