When first looking at the word electronegativity, we see the word electro at the beginning so it has to do with electrons which have a negative charge.
Electronegativity is a chemical property and it's how much an atom will be attracted to somebody else's electrons. An atom's electronegativity is affected by its atomic number which is the number of protons in its nucleus and how far away the valence electrons are from the nucleus. Valence electrons are the outermost electrons.