Mansplaining was a sexist phenomena when a male explained something to a female, often inaccurately, in a condescending or patronizing manner, as if the female would not have understood the subject in question otherwise.
In 2381, Beckett Mariner said she overheard Steve Levy mansplain the difference between a pork pie and a fedora to a cadet a few days previous, leading to a nightmare about fedoras. Mariner noted this to Brad Boimler when he asked if Jennifer Sh'reyan wore hats after he viewed a nightmare version of a Jennifer as a werewolf wearing a fedora. (LD: "Mining The Mind's Mines")