c'est à dire (Fr.). That is to say.
ceteris paribus (L.). Other things being equal.
chacun à son goût (Fr.). Every one to his taste.
chère amie (Fr.). A dear (woman) friend.
chef d'œuvre (Fr.). A masterpiece.
ci devant (Fr.). Formerly; heretofore.
comme il faut (Fr.). As it should be.
compagnon de voyage (Fr.). A travelling companion.
con amore (It.). With love; very earnestly.