rebel

From Middle English rebel/rebellen, from Old French rebelle/rebeller, from Latin rebellis and rebellō, meaning to wage war again or fight back — built from re- ("again") plus bellō ("to wage war").

The word entered English already carrying both its noun and verb forms from Old French, keeping close to its Latin root's sense of renewed warfare or insurgency.

It's a doublet of revel — both trace back to the same Latin verb rebellō, though English has pulled the two words toward very different meanings.