| Didaktik | didactics |
| didaktisch | didactic didactical |
| inaktiv | dormant |
| Praktik | practice |
| Taktik | military tactics |
| bioaktiv | bioactive |
| Dialektik | dialectic |
| deduktiv | deductive |
| direktiv | directive |
| Dianetik | dianetics |
| Nidation | nidation |
| Redaktion | editing |
| Aktie | share stock |
| Aktin | actin |
| Aktiv | active voice |
| aktiv | active |
| Einakter | one-act play |
| proaktiv | proactive |
| radioaktiv | radioactive |
| reaktiv | reactive |