Each atom has a different ability to draw
electrons to itself when it shares electrons (that drawing ability is
called Electronegativity).
A polar covalent means that an atom is electronegative, and the electrons are shared, but not equally.
So, if a bond between two atoms share electrons equally, then it is nonpolar and not electronegative.
If a bond between two atoms aren't shared equally, then it is polar and electronegative. Ex.) A polar molecule is water.