AV - evil 51, wicked 10, wicked one 6, evil things 2, misc 7; 76
1) full of labours, annoyances, hardships
1a) pressed and harassed by labours
1b) bringing toils, annoyances, perils; of a time full of peril to Christian faith and steadfastness; causing pain and trouble
2) bad, of a bad nature or condition
2a) in a physical sense: diseased or blind
2b) in an ethical sense: evil wicked, bad
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The word is used in the nominative case in Mt. 6:13. This usually denotes a title in the Greek. Hence Christ is saying, deliver us from "The Evil", and is probably referring to Satan.