| Term | Definition |
| despair | Utter hopelessness and despondency. |
| desperado | One without regard for law or life. |
| desperate | Resorted to in a last extremity, or as if prompted by utter despair. |
| despicable | Contemptible. |
| despite prep | In spite of. |
| despond | To lose spirit, courage, or hope. |
| despondent | Disheartened. |
| despot | An absolute and irresponsible monarch. |
| despotism | Any severe and strict rule in which the judgment of the governed has little or no part. |
| destitute | Poverty-stricken. |
| desultory | Not connected with what precedes. |
| deter | To frighten away. |
| deteriorate | To grow worse. |
| determinate | Definitely limited or fixed. |
| determination | The act of deciding. |
| deterrent | Hindering from action through fear. |
| detest | To dislike or hate with intensity. |
| detract | To take away in such manner as to lessen value or estimation. |
| detriment | Something that causes damage, depreciation, or loss. |
| detrude | To push down forcibly. |
| deviate | To take a different course. |
| devilry | Malicious mischief. |
| deviltry | Wanton and malicious mischief. |
| devious | Out of the common or regular track. |
| devise | To invent. |
| devout | Religious. |
| dexterity | Readiness, precision, efficiency, and ease in any physical activity or in any mechanical work. |
| diabolic | Characteristic of the devil. |
| diacritical | Marking a difference. |
| diagnose | To distinguish, as a disease, by its characteristic phenomena. |
| diagnosis | Determination of the distinctive nature of a disease. |
| dialect | Forms of speech collectively that are peculiar to the people of a particular district. |
| dialectician | A logician. |
| dialogue | A formal conversation in which two or more take part. |
| diaphanous | Transparent. |
| diatomic | Containing only two atoms. |
| diatribe | A bitter or malicious criticism. |
| dictum | A positive utterance. |
| didactic | Pertaining to teaching. |
| difference | Dissimilarity in any respect. |
| differentia | Any essential characteristic of a species by reason of which it differs from other species. |
| differential | Distinctive. |
| differentiate | To acquire a distinct and separate character. |
| diffidence | Self-distrust. |
| diffident | Affected or possessed with self-distrust. |
| diffusible | Spreading rapidly through the system and acting quickly. |
| diffusion | Dispersion. |
| dignitary | One who holds high rank. |
| digraph | A union of two characters representing a single sound. |
| digress | To turn aside from the main subject and for a time dwell on some incidental matter. |