What on earth are you talking about? Significant is plain English word with a straightforward meaning. How is it "fancy" or a "buzzword"? As for what it means:

What on earth are you talking about? Significant is plain English word with a straightforward meaning. How is it "fancy" or a "buzzword"? As for what it means: "important and deserving of attention; of consequence" (https://www.dictionary.com/browse/significant https://www.dictionary.com/browse/significant)