=Circum-=, _around_: circumference, circuit, circulate, circumvent.
=Cum-=, _with_, takes the forms com-, con-, col-, co-, cor-, under the influence of the letter following: compound, concord, collect, coöperate, correct, counsel.
=Contra-=, _against_: contradict; Fr., controvert, counterfeit.
=De-=, _down_, _from_: decline, deduct, decamp. It is negative in derange, deform, destroy; intensive in declare, deprave, despoil, desolate, desiccate.
=Dis-=, =di-=, _asunder_, _separation_: disarm, diffuse, disown, divorce; Fr., _des-_, _de-_ in defer, defy, delay, descant.
=Ex-=, =e-=, _out_, _out of_, _proceeding from_: exclude, exhale, ex-governor, extract, educe, elect, emanate, evade.
=Extra-=, _beyond_: extraneous, extraordinary, extravagant.
=In-=, _in_, _into_, _on_: infer, invade, invent. It also becomes il-, im-, ir-, before certain consonants, as illusion, improve, irrigate.
=In-=, _not_: incapable, illiberal, impious, irrelevant, ignoble.
=Inter-=, =intro-=, _among_, _between_, _within_: interfere, intervene, introspection.
=Male-=, _bad_, _ill_, _wrong_: malcontent, malpractice, maltreat.
=Mis-=, _ill_, _wrong_: misadventure, misalliance; Fr., mischief.
=Non-=, _not_: nonage, nonentity, nonsense.
=Ob-=, _toward_, _facing_, _against_: object, obstruct. It also becomes oc-, of-, op-: occur, offer, oppose.
=Per-=, _through_, often intensive, _throughout_, _thoroughly_--and so _wrongly_: perspire, pervade; persist, perturb, pervert; pellucid, pilgrim (see _ager_). Fr. _par-_: pardon.
=Post-=, _after_: postdate, posthumous, post-mortem, postscript.
=Pre-=, _before_: precede, precursor, preëmpt, premature, premise, prevent.
=Preter-=, _beyond_, _more than_: preterite (of past time), preternatural.
=Pro-=, _before_, _for_, _forward_: proceed, proconsul, prologue, pronoun, provide; _por_-tend. Fr., _pur_: purchase, pursue.
=Re-=, =red-=, _back_, _again_: rebel, recede, recover, redeem.
=Retro-=, _backwards_: retroactive, retrograde, retrospect.
=Se-=, =sed-=, _apart_: seclude, secrete, sed-i-tion (a going apart), segregate.
=Sub-=, _under_, _from under_: subject, subtract. It also becomes suc-, suf-, sug-, sum-, sup-, sur-, sus-, as in succor, suffer, suggest, supplant, suspend; subdivision (_i.e._, lower), summon (sub = slightly), surreptitious.