How to wear leggings?

nox
So, I have this pair of skin-tight black leggings that I want to wear with a super cute crop top, but when I wear them you can see the lines of my underwear! 
How do I wear the leggings without the underwear lines showing through?! 
EDIT: I will not be going without underwear, thank you very much! I alsowill not be wearing a long shirt, as the shirt I want to wear is a crop top. 
For everyone saying that I can't wear leggings as pants, or that I should buy thicker leggings, no. I can wear them as pants if I want to. Thanks. 
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