A German compound borrowed into English
German builds new words by fusing existing ones together, and Schadenfreude is one of the clearest examples: Schaden means "harm" or "damage," Freude means "joy," and stacking them gives you, transparently, "harm-joy." Duden, the standard reference dictionary for German, defines it as "boshafte Freude über das Missgeschick, Unglück eines andern": malicious joy at another person's mishap or misfortune.
English could also describe the feeling with a phrase. The rare English word epicaricacy has been used for it too. The presence of a German borrowing and a rare alternative does not establish that English lacked any way to name the feeling, or why the borrowing spread.
The specific feeling it names
The precision matters: Schadenfreude isn't pleasure at just anything bad happening, and it isn't wanting harm on someone in advance. It's the specific, narrower reaction of enjoying misfortune that has already happened to someone else: a rival sports team blowing a lead, a driver who cut you off getting pulled over two blocks later, a smug prediction aging badly. The emotion is common enough to be near-universal, but that observation alone does not establish why the word traveled between languages.
German dictionaries themselves don't fully agree on how much moral judgment to build into the definition. Duden's "boshafte Freude" leans into "malicious," while DWDS defines the same word without that qualifier, as simply pleasure at another's mishap. Psychologists studying the emotion generally treat it the second way: a description of a common reaction, not a verdict on the character of whoever feels it.
How to actually use it in an English sentence
In English, Schadenfreude functions as an uncountable noun, almost always used on its own, not pluralized or modified heavily: "There was more than a little schadenfreude in the office when the loudest critic's project got canceled." German capitalizes this noun. Merriam-Webster lists lowercase schadenfreude in English and also records the capitalized variant.
Pronunciation is the other thing that trips up new users: it's roughly SHAH-dən-froy-də, with the "sch" as an English "sh" sound and the final "e" pronounced as a short, weak vowel rather than silent.
It sits in the same category as words like déjà vu and senpai, borrowed expressions English uses in their original form. Their English uses can differ from those in the source language.
"Schadenfreude" isn't quite the same thing as "gloating"
English gloat overlaps with schadenfreude. Merriam-Webster defines the verb to include observing or thinking about something with triumphant, often malicious satisfaction, and gives gloat over an enemy's misfortune as an example. Gloating can therefore be private; it does not require an outward display or responsibility for the misfortune. Schadenfreude specifically names pleasure at someone else's mishap.
The terms overlap but have different ranges: gloat can also concern your own success, while schadenfreude specifies another person's misfortune. The Loanwords hub covers other borrowings, including senpai and mahalo.