According to oxford dictionary, to backstab means
The action or practice of criticizing someone in a treacherous manner while feigning friendship.
while to betray means
Be disloyal to
however, I have seen backstab and betray being used to mean "doing something that harms your friend"
I do not understand the difference.
For example, A trusts B with his bank account, but B steals from A by spending the money in A's account. Is that considered backstabbing as well? I understand that in this context, B has betrayed A's trust.
Best Answer
Your example:
...is both a betrayal and a "backstabbing."
A backstabbing is a specific kind of betrayal; it is a secret or covert betrayal. It is to betray someone "behind their back," thus "stabbing them in the back."
In romance, think of the distinction between "dumping" a partner (leaving them) and "cheating on" a partner. If a person says "I don't love you anymore, I'm leaving you" their ex-lover may feel betrayed but has not been backstabbed unless there was some secret before the breakup.
All backstabbings are betrayals, but they may be very small betrayals. A distant acquaintance or a coworker may not owe you any loyalty. That person can't "betray" you outright, but they can still "stab you in the back" by simply pretending to be friendly "to your face" while working secretly "behind your back" to hurt you.