单独、独自 by oneself

独来独往 Loner ; Playing by yourself ; keeping to oneself ; By myself but not alone

独奏、独唱 Solo

独奏/独唱 solo

独处/单独居住 be/live alone

独一无二的-独特的 unique-particular

独门独院 Single detached homes

独门独户 Single detached family

独断独行 be a law to oneself ; a law unto oneself ; Act arbitrarily