<p>Provided is a novel polyamide which has extremely low water-absorbing properties and satisfies moldability and impact resistance to a high degree. The polyamide is a copolyamide characterized by comprising (a) 50-98 mol% constituent units obtained from the equimolar salt of decanediamine with terephthalic acid and (b) 50-2 mol% constituent units selected from a group consisting of units of 11-aminoundecanoic acid, 12-aminododecanoic acid, undecanelactam, lauryllactam, and a mixture of these.</p>
