A dummy or mannequin was a life-sized model of a Human used for various purposes.
In 2266, James T. Kirk referred to a particular puppet, which he initially believed to be Balok, as "a dummy. A puppet of some kind." (TOS: "The Corbomite Maneuver")
In 2267, Hikaru Sulu compared a Black Knight that had just slain Leonard McCoy to a dummy. (TOS: "Shore Leave")
In 2366, while subduing a hologram of William T. Riker, Reginald Barclay referred to the officer as "a pretty mannequin in a fancy uniform." (TNG: "Hollow Pursuits")
Also that year, when shown male android Data by Kivas Fajo, Palor Toff mistook him for a mannequin. (TNG: "The Most Toys")
In 2373, The Doctor referred to other holograms of famous people as "Automatons, mannequin simulacra." (VOY: "Darkling")
Background information Edit
In a stage direction from the final draft script of TOS: "Miri", the interior of Biggs' toy store was said to include "some kid-sized mannequins, dressed as surfers and surferettes."
At least two mannequins were appeared in Star Trek: The Original Series, with one appearing as a Psi 2000 crew woman in "The Naked Time" and as the midform during the creation of android Kirk.
As Kirk's android midform