A garment for outdoor use, in particular a sports garment, for at least partially masking the shape of the buttocks, comprising: - at least one first trousers-shaped element (2, 102, 202, 302), including: - a front region (11, 111, 211, 311) suitable for positioning in and at least partially covering a central front part of the pelvis, - two lateral regions (5A, B, 105A, B, 205A, B, 305A, B) suitable for positioning in and covering each a portion of the body substantially extending from a lateral part (6A, 6B) of the pelvis to a lateral terminal part (Z1, Z2) of the buttocks, - a rear region (7, 107, 207, 307) suitable for positioning in and covering the buttocks, - two lower regions (8A, B, 108A, B, 208A, B, 308A, B) suitable for positioning in and separately covering each at least an upper part of the legs, and - a crotch region (10, 110, 210, 310) interconnecting at least said two lower regions (8A 8B, 108A, B, 208A, B, 308A, B); said first trousers element (2, 102, 202, 302) consisting of at least one first layer of material; characterized in that it comprises: - a second half-skirt element (13, 113, 213, 313) suitable for forming a rear half-skirt above said first trousers element (2, 102, 202, 302), - wherein said second half-skirt element (13, 113, 213, 313) is shaped and dimensioned: - so as to transversally extend only from one of said two lateral regions (5A, 105A, 205A, 305A) of the trousers element to the other (5B, 105B, 205B, 305B), and - so as to at least cover a part of the buttocks featuring a greater roundness and a lower terminal part of the buttocks, but not also an upper part of the buttocks, said half-skirt element (13, 113, 213, 313) leaving free and visible a portion of the trousers element (2, 102, 202, 302) that covers said upper part, and also leaving the front region (11, 111, 211, 311) of the trousers element (2, 102, 202, 302), suitable for covering the central front part of the pelvis, free and visible, - wherein said second half-skirt element (13, 113, 213, 313) is delimited: laterally by lateral extremal edges (14, 114, 214, 314), above by an upper edge (15A, 115A, 215A, 315A), and below by a lower edge (15, 115, 215, 315), - said lateral extremal edges (14, 114, 214, 314) being firmly attached each to a section of the lateral region (5A, B, 105A, B, 205A, B, 305A, B) of the underneath trousers element (2, 102, 202, 302), - said lower extremal edge (15, 115, 215, 315) not being attached by the underneath trousers element (2, 102, 202, 302), - said second half-skirt element (13 113, 213, 313) consisting of at least one second layer of material, separate and distinct from said at least first layer of material of the first trousers element (2, 102, 202, 302). - at least one first trousers-shaped element (2, 102, 202, 302), including: - a front region (11, 111, 211, 311) suitable for positioning in and at least partially covering a central front part of the pelvis, - two lateral regions (5A, B, 105A, B, 205A, B, 305A, B) suitable for positioning in and covering each a portion of the body substantially extending from a lateral part (6A, 6B) of the pelvis to a lateral terminal part (Z1, Z2) of the buttocks, - a rear region (7, 107, 207, 307) suitable for positioning in and covering the buttocks, - two lower regions (8A, B, 108A, B, 208A, B, 308A, B) suitable for positioning in and separately covering each at least an upper part of the legs, and - a crotch region (10, 110, 210, 310) interconnecting at least said two lower regions (8A 8B, 108A, B, 208A, B, 308A, B); - a second half-skirt element (13, 113, 213, 313) suitable for forming a rear half-skirt above said first trousers element (2, 102, 202, 302), - wherein said second half-skirt element (13, 113, 213, 313) is shaped and dimensioned: - so as to transversally extend only from one of said two lateral regions (5A, 105A, 205A, 305A) of the trousers element to the other (5B, 105B, 205B, 305B), and - so as to at least cover a part of the buttocks featuring a greater roundness and a lower terminal part of the buttocks, but not also an upper part of the buttocks, said half-skirt element (13, 113, 213, 313) leaving free and visible a portion of the trousers element (2, 102, 202, 302) that covers said upper part, and also leaving the front region (11, 111, 211, 311) of the trousers element (2, 102, 202, 302), suitable for covering the central front part of the pelvis, free and visible, - wherein said second half-skirt element (13, 113, 213, 313) is delimited: laterally by lateral extremal edges (14, 114, 214, 314), above by an upper edge (15A, 115A, 215A, 315A), and below by a lower edge (15, 115, 215, 315), - said lateral extremal edges (14, 114, 214, 314) being firmly attached each to a section of the lateral region (5A, B, 105A, B, 205A, B, 305A, B) of the underneath trousers element (2, 102, 202, 302), - said lower extremal edge (15, 115, 215, 315) not being attached by the underneath trousers element (2, 102, 202, 302), - said second half-skirt element (13 113, 213, 313) consisting of at least one second layer of material, separate and distinct from said at least first layer of material of the first trousers element (2, 102, 202, 302).