You may be confusing "effective neutral charge" and "effective nuclear charge". I have not heard of the former but the latter is the net charge felt by an electron from an atom. The two terms "effective nuclear charge" and "electronegativity" refer to different, but related, properties. The "effective nuclear charge" is that charge felt by an electron of a particular atom, the attraction between an electron and that atom. It is a result of the positive charge of the protons diluted by the negative charge of other electrons in the atom.
Electronegativity is a term used when talking about molecules, more than one atom. It refers to the tendency of the electrons which are shared between the atoms of the molecule to spend most of their time around one of the atoms.
The effective nuclear charge of one atom is just one thing to consider when figuring out the electronegativity. Effective nuclear charge is a large factor in electronegativity but not the only factor. Hence, the electronegativity of an atom in a molecule increases as the effective nuclear charge increases but it is not necessarily a direct correlation.