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 - The Parting of the Ways)

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

Sarah Jane Smith wore a burgundy and grey jumper with green diamonds when she and the Third Doctor helped to save Peladon from Azaxyr and Eckersley. (TV: The Monster of Peladon) She also wore a charcoal jumper when she, the Fourth Doctor, and Harry left the Ark to check Earth, (TV: The Ark in Space), met the Sontaran Field Major Styre, (TV: The Sontaran Experiment) and when she first sees Davros and some Mark IV Daleks on Skaro during the Dalek's origins. (TV: Genesis of the Daleks)

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)

Donna wore an eggplant purple turtleneck jumper when she corrected the paradox in the parallel world created by the Time Beetle. (TV: Turn Left)

Rachel Jensen wore a sky blue jumper with a turtleneck collar when she first met the Seventh Doctor. (TV: Remembrance of the Daleks)

Amy Pond wore a mauve jumper with a v-neck collar. (TV: The Pandorica Opens|The Big Bang)

Petronella Osgood wore a beige jumper. (TV: The Zygon Inversion|The Zygon Inversion)

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")