| Frechdachs | rascal |
| Flachdach | flat roof |
| freudsch | Freudian |
| Freifläche | open area open space |
| Brechzahl | refractive index |
| Rechtsachse | abscissa |
| Recherche | enquiry investigation |
| durchdacht | elaborate |
| Reetdach | thatched roof |
| wrachtach | in fact indeed really truly |
| Fregesch | Fregean |
| Fresssucht | gluttony |
| Freud'sch | Freudian |
| Freundchen | buster |
| frei machen | set free |
| freiheraus | outright |
| freimachen | stamp to postpone |
| freundlos | friendless |
| Frechheit | brashness cheek impudence |
| Freihafen | free port |