Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
-em
←
Proto-Celtic
*-mū
(inherited)
←
Proto-Indo-European
*-mō
(inherited)
→
Old Irish
luam
(affix)
→
Old Irish
féchem
(affix)