Chastity is a prostitute.
Chastity was working at a bar Dean takes Castiel to while they awaited for the arrival of Raphael, an archangel they wished to speak to. Chastity approached their table and asked for their names. Castiel struggled to say a word, so Dean told her his friend's name was "Cass". He then asked her name, to which she replied "Chastity".
Castiel proceeded to gulp down half a glass of beer.
Chastity then tugged Castiel out of his seat towards another room. Dean stopped them so he could give Castiel money to pay for her services. When Castiel resisted, Dean threatened to push him, leading Castiel to walk off and join Chastity.
Moments later, Chastity started screaming and yelling at Castiel in fury. Dean ran to her location and took Castiel away while two bouncers approached them. The two escaped through the back entrance.
Castiel informed Dean that he simply looked at her in the eyes and told her that it wasn't her fault her father Gene ran off, saying it was because he hated his job at the post office. Dean responded by telling Castiel that the whole industry ran on absent fathers.