Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Icelandic
Róbert
←
Proto-Germanic
*Hrōþiberhtaz
(derived)
←
Icelandic
Hróbjartur
(doublet)
→
Icelandic
Hróbjartur
(cognate)