From The Free Thought Project:
Stacks of papers, books, and folders cram into every available space on your desk, you glance at the clock to see it’s 2:31 a.m., and utter a swear word — you’re up late, again, but far too enmeshed in what you’re doing to even consider getting sleep yet. Perhaps your friends perceive you as an insomniac slob who swears too much; but they probably haven’t heard the good news: Studies suggest these traits are a sign of intelligence.
Popular mythology frequently equates swearing with low intelligence, limited vocabulary, and lower social status. But a study by psychologists Kristin Jay of Marist College and Timothy Jay of the Massachusetts College of Liberal Arts and published in the journal Language Sciences dispels those stereotypes.
Fluency in “taboo words,” they found, parallels fluency in mundane, neutral words — in fact, a billowing vocabulary of curses and slurs indicates a larger vocabulary overall. Those who swear abundantly generally tend to be more eloquent — “fluency is fluency,” the scientists found.
“A voluminous taboo lexicon may better be considered an indicator of healthy verbal abilities rather than a cover for their deficiencies,” the researchers wrote. “People who use taboo words understand their general expressive content as well as nuanced distinctions that must be drawn to use slurs appropriately. The ability to make nuanced distinctions indicates the presence of more rather than less linguistic knowledge, as implied by the POV [Poverty of Vocabulary] view.”
In other words, swearing is in no way indicative of a limited vocabulary, lack of intelligence, or hollow filler when someone can’t find anything better to say.