Jealousy and envious are two different words with the same meaning. They both mean that you for example want something someone else has. It's all a matter of grammatical correction when to use either one of those words. In the sentence I wrote, "envious" would not make sense, whilst "jealousy" does.
Allegedly. It has several meanings in that case, because that's the first time I've heard it's only used to explain a something being threatening. Pretty much every other place I've looked, it's linked to anxiety, fear, concern and insecurity. Meaning it can be used in a similar way to envious.