IPA: /mɪˈlɪtəntli/
KK: /mɪˈlɪtəntli/
In a way that shows a strong willingness to fight or argue for a cause.
She argued militantly for her beliefs during the debate.
Militantly → It is formed from "militant" (from Latin "militans", meaning serving as a soldier) and the suffix "-ly" (meaning in a manner of). The word "militantly" means in a manner that is aggressive or combative, as if one is serving in a military capacity.
Think of someone acting 'like a soldier' ('militant') when they are being aggressive or combative — that's what 'militantly' means.