The Drunken Lizard Pub

i have an icon below map area which says 'skill feat riposte ' what does this mean

You get this when your swordskill has reached level 10.
To use it you need to press the left shift key while attacking with a sword. It gives you a guaranteed hit (so use power mode for this) + a parry of all following enemy attacks, while this parry also deals damage to your enemies equal to the base damage of your sword.
It takes a little while for this special weapon feat to come up again, but the refresh time shortens when your sword skill improves.