Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
English
unbeknownst
←
English
unbeknown
(suffix)
←
English
st
(suffix)
→
English
beknownst
(back-formation)
→
German
unbekannt
(cognate)