Why does Beatrice refer to Benedick as Signior Mountanto? And what does "montant" mean?

I recall that Beatrice is using a pun on the word "montano", a word that has to do with fencing. She is trying to be humorous implying that Benedick "mountanto" is a bad at sword fighting. 

Beatrice asks about senor mountanto, which is her nickname for signor benedick. Whatcdoes that nickname indicate about her feeling for him/her attitude.

What is one insulting thing beatrice tells this mysterious man about benedick