Shawna is a variation on
Shauna, which is the female form of
Shaun, which is the anglicized form of
Sean, which is the Irish form of
John, which is taken from the Latin
Johannes, which is taken from the Greek
Ioannes, which is taken from the Hebrew
Yochanan, which means 'God is gracious'.
You could also follow the hyperlink of
Shauna :-).