The use of prefixes
Some words are formed with the help of a prefix. A prefix is a syllable placed at the beginning of a word to qualify its meaning and form a new word. Most of the prefixes in English have been borrowed from Latin and Greek. A few are from old English. A list of the most important prefixes is given below.
Ambi (on both sides): ambidextrous, ambivalent, ambiguous
Anti (against): antidote, anti-social, anti-national
Auto (self): autobiography, autocrat, automatic, autograph
Bene (well): benediction, benevolent, benefit
Bi (two, twice): bilateral, bigamy, biweekly, bisect
Circum (around): circumference, circumnavigation, circumstance, circumscribe
Co (with): cooperate, coordinate, co-existence, coalition
Contra, counter (against): contradict, contravene, controversy, counteract, counterbalance
De (down): dethrone, defame, demoralize, denationalize
Demi (half): demigod
Dis (apart): disconnect, discord, disorganize, dispassionate
Extra (beyond): extraordinary, extravagant, extraterritorial
Hyper (over): hypercritical, hypersensitive, hypertension
Mono (alone): monogamy, monopoly, monotheism, monotony
Non (not): nonviolent, nonsense
Omni (all): omnipresent, omnipotent, omnivorous, omniscient
Poly (many): polygamy, polytheism, polysyllabic
Post (after): post-war, post-script, post-mortem
Pre (before): pre-war, precaution, premature, prefix, prehistoric
Pro (for): pro-American, pro-communist
Pseudo (false): pseudo-classic, pseudonym
Re (again): return, refund, revive, research
Semi (half): semicolon, semi-final, semi-formal, semi-official
Sub (under): subconscious, sub-human, sub-caste, subordinate, subjugate
Super (over): superman, supernatural, superhuman, supervise, surpass, surcharge, surplus
Trans (across): trans-Atlantic, transcribe, transcend
Tri (three): tricolor, trinity, triangle
Ultra (beyond): ultramodern, ultraviolet
Un (not): unnatural, unbalanced