Cover up is a more common word and it is used to make someone's skin look flawless.

Large, beautiful breasts that are keep well consealed and initially appear to be much smaller and less impressive than they actually are until unleashed.

When used excessively, it can make your face look like a shiny orange orb. Whenever you can tell that someone is wearing foundation, they are wearing too much. Sometimes when not rubbed in correctly, over-applied, or the person in question has applied the wrong shade, they can get the mask effect. Foundation is used excessively by teenage girls, specifically bro ho's and girls who work in Abercrombie.

Girls wear it. Mostly worn with other forms of makeup. Can come in a cream, or as powder. Used to make skin seem perfect and fault-less. Applying too much makes them look like slutty fake barbie-dolls. But foundation is good if you want to hide freckles and blemishes.

n. a term used widely until the 1970s to describe various women's undergarments such as girdles, bustles, corsets, etc. Girdles and corsets slimmed down the moderately obese lady who could tolerate them. Corsets also gave an hourglass figure to a thin person, such as Scarlett O'hara.

it is the lowest level of 'smartness' at standard grade level and is used to abbreviate someone being in a foundation class (stupid class) with the use of the single word 'foundation' or shortened to 'foundy'. It can also be used to describe someone's actions to be like those of a person in a foundation class.

a huge amount of makeup to conceal or to make an ugly girl look more respectable.