A BACKSTABBER is someone who betrays another person's trust by acting in a deceitful or malicious manner. The term 'BACKSTABBER' can be used to describe someone who is willing to hurt or betray another person for their own gain. Two words that can be used to describe a BACKSTABBER are 'RAT' and 'JUDAS'. The word 'RAT' is a three-letter word that means to inform on someone, while the word 'JUDAS' is a five-letter word that refers to the disciple who betrayed Jesus in the Bible.