A letter or group of letters added to the start of a word to make a new word which can create a opposite meaning to the attached word.
Prefixes are added before either simple roots or complex bases. Below are some of the common prefixes examples.
| Prefix | Definitions | Examples |
| Negative Prefixes | ||
| a | not or without | amoral, apolitical,atheist, atypical |
| anti | against | antitrust, antisocial, antifreeze, antibody |
| dis | opposite of | disbelief, distrust, disuse, distaste |
| in/im | not | independent, inexcusable, inerrant immature impossible |
| mis | badly wrongly | misbehave, mislead, misuse, mistrust |
| un | not | unbelievable, untrustworthy, uncooked, unchanged, uncommon, unimportant |
Prefixes Showing Amounts |
||
| mono | one, single | monocle, monologue, monogamy, monopoly |
| uni | one | unicycle, unisex,unit |
| bi,du | two | bicycle, biped, duet, dual, duplex |
| tri | three | tricycle, tripod, triathlon, triplet |
| quadr | four | quadruple, quadrant, quadruplet quadruped |
| multi | many | multiplex, multitude, multivitamin, multicultural |
| semi | half | semicircle, semifinal, semiannual, |
Prefixes that Show Places and Directions |
||
| ad | toward | adjoin, advance |
| ante | before/front | antecedent, antebellum, antechamber |
| circum | around | circumvent, circumference, circumnavigate |
| post | after | postlude, postdate, postpone, post |
| sub | under | submarine, subzero, subsoil |
| re | back/again | redo, repaint, repeal, repeat |
| retro | back | retroactive, retro |
| trans | across over | transmit, transatlantic, transplant |