Nonpolar amino acids are the amino acids that are not charged (neither positive or negative) or more precisely, amino acids that are neutral in nature due to them having equal numbers of amino and carboxyl groups.
What are Nonpolar Amino Acids?

Nonpolar amino acids are the amino acids that are not charged (neither positive or negative) or more precisely, amino acids that are neutral in nature due to them having equal numbers of amino and carboxyl groups.