n. to describe a person who is 'Full Of Shit', and treats those who try to help them with disrespect.
Person 1: 'I'm not coming to my doctor's appointment today because you didn't tell me I had to pay anything.'
Person 2: 'Don't be such a FOS.'
Person 2: 'Don't be such a FOS.'
by Maria Espia March 18, 2008
v. to purge oneself of personal intimate information as normal conversation to disinterested strangers, acquaintances or colleagues.
by Maria Espia March 18, 2008