Something deviant strays from what's considered normal, standard, or expected. The word describes behavior, ideas, or characteristics that depart from accepted patterns or rules.

In statistics, a deviant data point falls far outside the usual range: if most students score between 70 and 90 on a test, a score of 15 would be deviant. In sociology, deviant behavior breaks social norms or rules: cutting in line, cheating on a test, or speaking loudly in a library are all deviant acts because they violate expected conduct.

The word carries a negative connotation. While we might admire someone who's unconventional or original, calling something deviant suggests it's not just different but wrong or problematic. A deviant route from the hiking trail might lead you into danger. Deviant behavior in a classroom disrupts learning.

Scientists and researchers use “deviant” more neutrally to mean simply “different from the norm,” but in everyday conversation, the word usually implies disapproval. Think of it as the difference between saying someone is unique versus saying they're weird: one celebrates difference, the other criticizes it. Deviant leans toward the critical side.