de
de — prefix
1. A prefix that you add to the beginning of a verb or noun to give it the opposite
A prefix that you add to the beginning of a verb or noun to give it the opposite meaning, or to show that something is taken away, removed, or made smaller.
The company decided to deactivate the old security system after the upgrade.
de- + activate → deactivate (reverse action)
Large areas of forest near Kyoto have been deforested to build new roads and houses.
de- + forest → deforest (remove trees)
Ambassador Kwame took steps to de-escalate the tension between the two nations.
Programmer Elena spent the whole afternoon debugging the code before the launch.
General Omar agreed to declassify the old military records after thirty years.
- un-
The most common reversal prefix in English; attaches to a wider range of words than de- (e.g., undo, unpack, unwrap). De- tends to sound more formal or technical.
- dis-
Also adds opposite or negative meaning, but often carries a sense of 'apart' or 'away' (e.g., disagree, disconnect, disapprove). Less about removal and more about negation or separation.
- anti-
Means 'against' rather than 'reverse' or 'remove' (e.g., anti-war, anti-virus). Used with nouns and adjectives, not typically with verbs.
- re-
Means 'again' or 'back' — the opposite direction from de- (e.g., activate → deactivate / reactivate; classify → declassify / reclassify). Re- restores or repeats; de- reverses or removes.
文法句型
de- + [verb] — forms a verb with opposite or removal meaning
de- + [noun] — forms a noun meaning removal or reduction of something
用法筆記
This prefix has three main jobs: (1) reversing an action (deactivate, declassify, defrost); (2) removing something (debug, deforest, de-ice, decontaminate); (3) reducing or lowering (de-escalate, devalue, downgrade is less common, but de-emphasize works). The prefix attaches most naturally to verbs and nouns that come from Latin or French roots. Avoid inventing new de- words — check a dictionary first, as not every verb or noun accepts this prefix.