Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*kaxtos
→
Welsh
caeth
(inherited)
→
French
chétif
(derived)
→
Old French
caitif
(derived)
→
Irish
cacht
(inherited)
→
Old Irish
cacht
(inherited)