The phrase "black jumper" refers to a piece of clothing typically worn during colder months. It is a sweater or pullover that is entirely black in color.
Sentences with «black jumper»
Have you seen something small and black jump from the sofa onto your arm? (fallsroadvet.com)
Another glamour black leather jacket with fur lining is styled with black jumper, black mid-rise skinnies and wedge runners: (fashiongum.com)