I knew about Grace O'Malley, who was an Irish thorn in Good Queen Bess' pride. Jeanne de Clisson [13oo ~ 1359] is rather more interesting though not quite as much fun.
She was first married off at 12 & must have been a pretty hardy lady because she survived childbirth twice & outlived her husband. By 16 she was married to her 2nd husband & produced another 5 children. In that time & place that alone was something of a miracle.
The politics are a bit complicated but when Philip VI beheaded her beloved Oliver she got a tad upset, sold of the family jewels & property & invested the proceeds in 3 warships. The warships she painted black with red sails & with these she marauded the English channel after any French ships she could get her hands on. If caught by Jeanne your chances of survival were zilch. She was neither a kind nor forgiving lady, personally executing any aristocrat foolish enough to be aboard his own vessel. However she did always spare 2 or 3 crew ensuring that Philip heard that the Lioness of Brittany had struck again.
I bet Philip really regretted upsetting that particular lady!