Jim Kirk’s legendary ego was bruised when he was called Captain Dunsel in Star Trek: TOS, but what does the insult mean, and why throw it at Kirk?

While Captain James T. Kirk (William Shatner) commanded a great deal of respect from his crew in Star Trek: The Original Series, he once earned himself the insulting title of “Captain Dunsel.” Captain Kirk was a Starfleet legend, whose exploits would go on to inspire future generations of officers from Star Trek: The Next Generation to Star Trek: Lower Decks. However, this legendary status could have been scuppered had things gone according to plan in the Star Trek: TOS episode, “The Ultimate Computer.”

In Star Trek: The Original Series season 2, episode 24, “The Ultimate Computer”, Starfleet came up with the ingenious idea to replace Kirk with a computer. Designed by Doctor Richard Daystrom (William Marshal), the M-5 multitronic unit (voiced by Scotty actor James Doohan) was brought aboard the Enterprise to test its capabilities. The battle drills soon became a desperate fight for life when M-5 became solely focused on its own self-preservation. Captain Kirk defeated M-5 when he convinced it to self-destruct, putting an end to any suggestions that he was the Enterprise’s Captain Dunsel.

What Captain Dunsel Means & Why Kirk Was So Insulted

In “The Ultimate Computer”, Commodore Bob Wesley (Barry Russo) wryly referred to Kirk as Captain Dunsel, clearly wounding the Enterprise Captain’s pride. After Kirk had left the bridge, Spock explained that a “dunsel” was a term used by Starfleet midshipmen to describe a part of the ship that was no longer useful. With a computer in charge of the running of the Federation’s flagship, there was a very real risk that Kirk would become redundant, the dunsel. Thankfully for Kirk, the M-5 was no replacement for a human being, proving that he was still incredibly useful aboard the Enterprise.

Interestingly, dunsel isn’t listed in the Oxford English Dictionary, suggesting that unlike a lot of terms in Star Trek, it’s not rooted in ancient nautical traditions, as some have suspected. The first recorded usage of “dunsel” is in the script for “The Ultimate Computer” by Star Trek writer D.C. Fontana. There’s a company specializing in bags made from upcycled sails and marine textiles called Dunsel’s, that has adopted the nautical implications of Fontana’s potentially made-up word. Brilliantly, however, the concept of using recycled materials to reduce wastage is very much in the spirit of Star Trek.

Starfleet Made The Same A.I. Mistake In Star Trek: Lower Decks

A century later, Admiral Les Buenamigo (Carlos Alazraqui) tried to succeed where Richard Daystrom had failed. In Star Trek: Lower Decks‘ season 3 finale “The Stars at Night”, Buenamigo rolled out his new Texas-class starships, which threatened to make California-class starships like the USS Cerritos into dunsels. Like Daystrom’s M-5, the Texas-class starships also had a fault in their programming, which turned the entire armada against Buenamigo and Starfleet. Hilariously, Ensign Sam Rutherford (Eugene Cordero) insulted the hostile A.I. when he threatened to make it dunsel if it didn’t stop attacking Douglas Station.

If that wasn’t bad enough, Star Trek: Picard season 3 revealed that Starfleet had failed to learn from the mistakes of Daystrom and Buenamigo. Fleet Formation Mode was installed on all starships, handing control of the entire Starfleet armada over to A.I. Tragically, this was hijacked by the Borg Collective, who used it as a last ditch attempt to destroy all organic life. It was only thanks to the USS Enterprise-D and Commodore Geordi La Forge (LeVar Burton) that the crisis was averted. A century on from Star Trek: The Original Series, and despite Starfleet’s best efforts, there’s still no such thing as Captain Dunsel.