Blonde

Blonde, sometimes spelt blond, was a hair colour. Several of the Doctor's companions were blonde, such as Rose Tyler, (TV: Father's Day) Chris Cwej (PROSE: Original Sin) and Romana II. (TV: Destiny of the Daleks) After the Thousand Year War, all Thals had blonde hair. (TV: The Daleks, Planet of the Daleks) Karfelon androids were also all blonde. (TV: Timelash)

Three incarnations of the Doctor had blonde hair, specifically the Fifth, Sixth and Thirteenth Doctors. (TV: Logopolis, The Caves of Androzani, Twice Upon a Time)

Blonde women, in particular, were specifically attractive to men. When Martha Jones asked Jack Harkness whether or not the Tenth Doctor "just [got] bored of us" and abandoned his companions after a while, he replied, "Not if you're blonde", referring to Rose Tyler. Martha was annoyed with this. (TV: Utopia) Donna Noble also commented to Rose that "blonde may work on the men but it won't work on me." (TV: Turn Left)

"Blonde" was also used as an insult to indicate stupidity. Esther Drummond was once asked, "How blonde are you?" when she attempted to leave the San Pedro Overflow Camp during a lockdown. (TV: The Middle Men)