Examples: cartography card archaeology archetype monarchy legal loyal purse personal cinema kinase car carpenter hippopotamus Mesopotamia dative data date
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Welsh sicr
Old English sicor (derived)
Welsh segur (doublet)
English sicker (cognate)
Middle English siker (borrowed)
Proto-West Germanic *sikur (derived)
Latin sēcūrus (derived)

Welsh segur (doublet)
Welsh sicrhau (affix)