Some one who acts hard but is really soft like a pop tart is hard on the outside but, soft in the middle.

One of the many attempts to create an N-word like term to describe white people. Essentially, whenever a white person is acting ignorant or foolish, or simply too white, one may call them a poptart.

used to describe those who are under the influence of extreme ditzyness and/or insane insucurities that cause them to act exactly like everyone els in the poptart population!! Often found gossiping about everyone(even their own kind)flirting or playing hard to get with every male that has a pulse, or making fun of random individuals just because they're different. Poptarts are usualy described as bitches or glowing angels.
WARNING: if one of the poptarts ever askes you to join they're 'group' be prepared to be sucked in, become beutiful but also a backstaping bitch, and drop about 50 pionts off your IQ.

Actually, the use of "pop-tart" as an adjective for a slatternly pop singer was first coined by Mark Hänser in the Long Beach (California) Union Daily in 1983, first in reference to "Pat Bena-tart" then famously about Scandal's Patty Smyth (of "Goodbye To You" and "The Warrior" fame.)

basically this is anyone who is considered a space case, twink, or ditz. It is usually referring to girls but it can apply to guys as well. the person must be in high school and must be considered to be one of the "popular" group. this is what the "pop" in poptart refers to. the "tart" part of it is easy: fake, slightly stupid, and annoying. Tart is an old insult so it makes sense here.

a high class girl who lacks mental capacity.
flaky on the outside, not much on the inside

A boy or girl that is 12-19 years old. Can be used to refer to a typical teenager. The only thing that most kids of the latter age know how to do is cook instant noodles and pop tarts.