what does it mean when you are easily offended over words people use?

I am not sure that the word is the problem in itself.  It could be that the use of that word sent you a message about her attitude and the attitude is what pissed you off.

What does it mean, that this happens?  There is no general answer apart from the obvious idea that you were offended for some reason.

If a word has an automatic response with you, though, it is because you have learned to respond that way to the word. Hard to say why that learned response exists for you in particular.  I have a negative reaction when people say "tipping point" or "triggered", because those words are associated in my mind with certain attitudes and world-views which I find annoying (or worse, I really dislike because I think they are wrong as wrong can be).

In my experience (including dealing with behaviors that I do not like yet I do/did), it is helpful to first understand WHY the response exists, and then fix that mistake in your training (break the association; retrain yourself).  Cognitive behavioral modification (the term for this method) is not useful for everyone though.  It has worked for me.