A Keyboard Warrior is someone who deliberately sends inflamatory,rude, agressive or derogatory emails for the purpose of making the recipient of the email get angry or upset.
He/she will also generally Copy as many people as possible on the email, becuase they are under the erroneous impression that they are being witty/funny and that everyone will agree with their comments.
In person they are usually quite timid and do not like direct confrontation. They generally have deep rooted mental issues of depression and or rejection usually becuase they have small dicks and they were breast fed till the age of 10.
Keyboard Warrior - Aaron Liu