That led to a much more important question, namely: is it magnonymity (like anonymity)? Magnanimosity (like animosity)?
In the end, I didn't pay for half.
Thanks to Leo for answering the two-million dollar question.
n. pl. mag·na·nim·i·ties
1 : the quality of being magnanimous : loftiness of spirit enabling one to bear trouble calmly, to disdain meanness and pettiness, and to display a noble generosity
2 : a magnanimous act