Bruce Lucier was an acquaintance of Julian Bashir.
In 2367, he held a New Year's Eve party at his home which Bashir and his Andorian friend Erit attended. Elizabeth Lense was also present at the gathering. During the party, another guest pointed out Erit to Lense and told her that the Andorian was Bashir. Lense went on believing Bashir to be an Andorian for the next four years. (DS9: "Explorers")
This character was only mentioned in dialogue.
The nature of his acquaintance with Bashir and Lense is unknown, although it seems likely he was another medical student. The Star Trek Encyclopedia, 4th ed., vol. 1, p. 491 identifed him as a medical student at Starfleet Medical School.