For me atleast I came to the conclusion that I get blocked due to a deep ptsd response on certain words. I think it's because in my youth I stuttered in front of people and was viciously abused for it so the pain of "saying that specific word" still tenses me up and raises my adrenaline high enough to cause a block even in adulthood. If there was a way to lower stress enough or get ride of that memory all together I think we wouldn't get blocked any more. But for now that's basically impossible. The block is basically you thinking that saying this word is going to cause people to hurt you or cause you immense shame.