Abstract: The invention relates to a copolyamide comprising units resulting from the polycondensation reaction of the following precursors: terephthalic acid (a), an aliphatic diamine (b) comprising x carbon atoms, x being an integer between 6 and 22, and an aminocarboxylic acid and/or a lactam (c) comprising a main chain and at least one linear or branched alkyl branching, the total number of carbon atoms of the aminocarboxylic acid and/or of the lactam (c) being between 12 and 36. The invention also relates to the process for preparing said copolyamide and to a composition comprising such a copolyamide.