Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Icelandic
kunnur
←
Proto-Germanic
*kunþaz
(derived)
←
Proto-Germanic
*kunnaną
(derived)
←
Proto-Indo-European
*ǵneh₃-
(root)
←
Old Norse
kunnr
(derived)
←
Old Norse
kuðr
(mention)
→
English
couth
(mention)