Meaning of DE- in English

DE-

de- BrE AmE ˌdiː, di, də —Attached to free forms, meaning 'do the opposite of' or 'remove', this prefix is usually pronounced strong, ( ˌ ) diː ( ˌ de ˈ nasalized) . With these meanings it is freely productive, and most words made this way are not included in the dictionary. Otherwise the prefix is usually weak, di (de ˈ cide, de ˈ pend), with variant də ; but strong ¦de+ before an unstressed syllable ( ˈ deference, ˌ dere ˈ liction).

Longman Pronunciation English Dictionary.      Английский словарь произношений Longman.