@Cossue, good morning and thank you.
I finally found out one possible root for the germanic
-nand: kunnandi=knowledge, huggjandi=wisdom, leikandi=sport, jest. Sisu+nandi, he who knows about the carmen funebre, the ritual funeral singing. I believe nanþaz is a better option, because the ancient peoples loved to attribute glorious, courageous, daring names to their children.
However, there is Bustamante.
Boustom is attested in the Botorrita plaques as meaning
stable, corral. The very root of
boustom, could be from protoceltic
bow (bull, cow). This leaves us with the
-ante termination. Therefore, while there is a germanic
-and, -andi, -ande termination, it seems that there is also
-ante, which is probably not germanic but perhaps iberian, celtiberian or celtic? If this is true, what would be the possible meaning of
-ante? This is where I got stuck.
Please, let me know your thoughts about
-ante.