Jumper

A jumper was an item of clothing, often worn over a shirt, made of knitted wool.

The Fifth Doctor wore two similar cricketing jumpers under his two coats. (TV: Castrovalva onwards, The Awakening onwards) Similarly, the Seventh Doctor wore a sleeveless pullover, covered in turquoise zig zags and red question marks, (TV: Time and the Rani onwards) whilst the Twelfth Doctor wore a jumper patterned with holes. (TV: Listen et al.) The Thirteenth Doctor sometimes wore jumpers in navy blue (TV: Spyfall) or cobalt blue. (TV: Orphan 55)

The Ninth Doctor dressed almost exclusively in long sleeve V neck jumpers, worn underneath his leather peacoats. (TV: Rose onwards)

Barbara Wright often wore a beige turtle-neck jumper. (TV: The Keys of Marinus, The Web Planet, The Space Museum, The Chase, etc.)

While visiting Fang Rock, Leela wore a grey jumper. (TV: Horror of Fang Rock)

Martha Jones wore a navy blue jumper with a v-neck collar, as did her clone when posing as her. (TV: The Sontaran Stratagem|The Poison Sky)

Information from invalid sources
Deborah (as played by Minnie Driver in the Doctor Who serial Father Time) had a "dowdy" appearance, as described by a costume designer, executed using unflattering jumpers and corduroy trousers. (NOTVALID: Father Time: "Set Visit")