| Term | Definition |
| retroactive | effective as of a prior date |
| To retrocede | to go back; to recede |
| retroflex | to bend back |
| retrogression | a stepping backward |
| retrospect | to look back as in a look on to the past |
| To retrovert | to turn back |
| To procrastinate | to delay; postpone |
| progenitor | ancestor; forefather |
| prognosis | forecast, prediction |
| To progress | to move ahead; to go forward |
| prolix | unduly prolonged |
| prologue | introduction to a discourse, poem etc. |
| promiscuous | indiscriminately distributed |
| prophet | one who speaks of things ahead (forward) |
| prophylactic | a measure or device used to guard from things |
| To propone | to put forward |
| To prospect | to look forward |
| To prostrate | to lay flat on the ground; to throw down; |
| To propound | to propose; to offer for consideration |