Prefixes The 20 Most Common Prefixes in English Un+Meaning: not Unhappy Untied Unloved Unopened Re+Meaning: again Rebuild Rewrite Retake Reread Im-, In-, Ir-, Il+Meaning: not Impossible Injustice Irresponsible Illegible Dis+Meaning: not; opposite of Disloyal Disobey Dislike Disagree En-, Em, +Meaning: put in, go in; cause to Encode Encage Emblaze Embed Non+Meaning: not Nonhuman Nonfat Nonsense Nonthreatening In, Im+Meaning: Into, inside, within Inbound Infield Immigrant Imprison Over+Meaning: over; too much Overuse Overeat Overcook Overweight Mis+Meaning: bad, wrong Misspell Misunderstand Misfire Misconduct Sub+Meaning: below, under; less than Submarine Subsoil Subzero Subhuman Pre+Meaning: before Prehistoric Prefix Preschool Prewrite Inter+Meaning: between, among International Interstate Interact Internet De+Meaning: make opposite of, remove, reduce Deice Dethrone Defrost Decriminalize Fore+Meaning: before, in front of Forecast Forerunner Foreground Foreshadow Trans+Meaning: across, beyond, change, through Transatlantic Transform Transcontinental Transport Super+Meaning: above, over Supercharge Superimpose Superfine Superstar Semi+Meaning: half, partially, twice during Semcircle Semisweet Semiconscious Semimonthly Anti+Meaning: opposite, against Antifreeze Antiwar Antibody Antibiotic Mid+Meaning: middle Midstream Midway Midday Midair Under+Meaning: beneath, below, less Underage Underweight Undersea Undercooked