| 1. | habitually or characteristically accepting or tolerant of something, as social behavior or linguistic usage, that others might disapprove or forbid. |
| 2. | granting or denoting permission: a permissive nod. |
| 3. | optional. |
| 4. | Genetics. (of a cell) permitting replication of a strand of DNA that could be lethal, as a viral segment or mutant gene. |