Electron affinity: It is defined as the amount of energy released when an isolated gaseous atom accepts an electron to form a monovalent gaseous anion. The magnitude of electron affinity measures the tightness with which the atom can hold the additional electrons.
It is expressed either in electron volt per atom or kilojoules per mole of atoms.
Electronegativity: It is the tendency of an isolated gaseous atom to attract the shared electron pair towards itself. It is not the property of an isolated atom-like EA but the property of an atom that may be bonded to one or more atoms in a molecule.