'Evil' is an adjective and 'devil' is a noun.

Evil means:


Main Entry: 1evil
Pronunciation: 'E-v&l, British often and US also 'E-(")vil
Function: adjective
Inflected Form(s): evil·er or evil·ler; evil·est or evil·lest
Etymology: Middle English, from Old English yfel; akin to Old High German ubil evil
Date: before 12th century
1 a : morally reprehensible : SINFUL, WICKED <an evil impulse> b : arising from actual or imputed bad character or conduct <a man of evil reputation>
2 a archaic : INFERIOR b : causing discomfort or repulsion : OFFENSIVE <an evil odor> c : DISAGREEABLE <woke late and in an evil temper>
3 a : causing harm : PERNICIOUS <the evil institution of slavery> b : marked by misfortune : UNLUCKY
- evil adverb, archaic
- evil·ly /-(l)E/ adverb
- evil·ness /-n&s/ noun  

And devil:

devil
 
SYLLABICATION: dev·il
PRONUNCIATION:   dvl
NOUN: 1. often Devil In many religions, the major personified spirit of evil, ruler of Hell, and foe of God. Used with the. 2. A subordinate evil spirit; a demon. 3. A wicked or malevolent person. 4. A person: a handsome devil; the poor devil. 5. An energetic, mischievous, daring, or clever person. 6. Printing A printer's devil. 7. A device or machine, especially one having teeth or spikes and used for tearing. 8. An outstanding example, especially of something difficult or bad: has a devil of a temper. 9. A severe reprimand or expression of anger: gave me the devil for cutting class. 10. Informal Used as an intensive: Who the devil do you think you are?
TRANSITIVE VERB: Inflected forms: dev·iled or dev·illed, dev·il·ing or dev·il·ling, dev·ils or dev·ils
1. To season (food) heavily. 2. To annoy, torment, or harass. 3. To tear up (cloth or rags) in a toothed machine.
IDIOMS: between the devil and the deep blue sea Between two equally unacceptable choices. full of the devil Very energetic, mischievous, daring, or clever. give the devil his due To give credit to a disagreeable or malevolent person. go to the devil 1. To be unsuccessful; fail. 2. To become depraved. 3. Used in the imperative to express anger or impatience. play the devil with To upset or ruin. the devil take the hindmost Let each person follow self-interest, leaving others to fare as they may. the devil to pay Trouble to be faced as a result of an action: There'll be the devil to pay if you allow the piglets inside the house.
ETYMOLOGY: Middle English devel, from Old English dofol, from Latin diabolus, from Late Greek diabolos, from Greek, slanderer, from diaballein, to slander : dia-, dia- + ballein, to hurl; see gwel- in Appendix I.

HTH


Sheila

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Note added at 2003-03-19 08:42:31 (GMT)
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Sorry, I forgot to add, as you can see, the word \'devil\' is also used as a verb.

in Christianity devil is an invisible "person" opposit to angel

evil - result of devil's activity

hope it helps :)

devillish would be the adjective

could also use:
fiendish
malignant
malevolent
evil
wicked
vindictive

hth

does not mean that those countries are the Devil, but it is implied. Evil can be used in many ways, as pointed out in the other answers. One way to put is is that the Devil is evil, but evil does not always have to do with the Devil, especially when non-Christians are speaking.