il penseroso (It.), the pensive man.
ils n'ont rien appris ni rien oublié (Fr.), they have learned nothing and forgotten nothing [said of the French Emigrés, often of the Bourbons].
impar congressus Achilli (L.), unequally matched against Achilles.
impasse (Fr.), a cul-de-sac, an insoluble difficulty.
impayable (Fr.), invaluable.
impedimenta (L.), luggage in travelling: the baggage of an army.
imperium et libertas (L.), empire and liberty.
imperium in imperio (L.), a government within another.
in abstracto (Late L.), in the abstract.
in articulo mortis (L.), at the point of death.