Described by Harry as "a hard-faced Slytherin girl" (PS8) and as having a face like a pug (PA6, GF27). She was the ringleader of a "gang of Slytherin girls" (OP25), and she doted on Draco Malfoy; she showed considerable concern when he was gored by a hippogriff during their first Care of Magical Creatures lesson (PA6), and was Draco's date for the Yule Ball (GF23). Like Draco, Pansy tends to pick on and try to intimidate those who are weaker -- or just different -- than she.
Pansy’s true colors – not to mention her sheer stupidity – showed through the night of the Battle of Hogwarts, when she heard Voldemort’s demands for Harry to be turned over and yelled for someone to grab him. McGonagall made sure she was the first one out the door (DH31).
Possible name origin
A pansy is a kind of violet. In magical terms, it is noteworthy for its appearance in Shakespeare's play "A Midsummer Night's Dream," in which it is referred to by its other name of "love-in-idleness." In the play, Puck used the juice of the pansy to cause most of the trouble, squeezing drops of it onto the eyes of unsuspecting sleepers to cause them to fall in love with the next creature they saw. We do not know if the juice of the pansy has similar properties in the Harry Potter universe, however. -- MLW
In the movies
The role of Pansy Parkinson is played by Genevieve Gaunt (IMDb).