Tear

Tears, or lachrymatory secretions, were the liquids secreted from an individuals' eyes during the act of crying. This could be caused by stress or pain, (COMIC: The Infinite Astronaut) as well as grief, guilt, anger and panic. (AUDIO: Harvest of the Sycorax)

The automatic visor washers Carl Readon installed in the robot, Robbie allowed him to produce tears. (COMIC: Doctor Who and the Robot)

After Heather became a sentient oil creature, she "left her tears" with Bill Potts. (TV: The Pilot) After being cyberconverted, Bill cried, (TV: World Enough and Time) with the Twelfth Doctor later assuring her "where there's tears there's hope". Heather traced Bill by the tears Heather left her, and made her another sentient oil creature. Bill, in turn, saved the Doctor with her tears. (TV: The Doctor Falls) Nardole held the opinion though that "the Doctor never notices the tears." (TV: The Pilot)

As a Cyberman, Yvonne Hartman cried oil. (TV: Doomsday)

Oswin Oswald broke down in tears when she was forced to confront that she had been turned into a Dalek. (TV: Asylum of the Daleks) Linked to Francesca Latimer, the Great Intelligence's snow storm turned to tears when the girl began weeping at the death of Clara Oswin Oswald. (TV: The Snowmen) When the Twelfth Doctor had his memories of her wiped, Clara Oswald cried. (TV: Hell Bent)

Rose Tyler cried when she separated from the Tenth Doctor in Pete's World. After a last goodbye, the Doctor likewise shed a tear. (TV: Doomsday)

References

The Eleventh Doctor described his time stream as "the tracks of [his] tears". (TV: The Name of the Doctor)