I'd say "Sagacity" is definitely a very rare word in English, certainly less common than "paradoxical". It is often the case in English that a Romance loan is c

I'd say "Sagacity" is definitely a very rare word in English, certainly less common than "paradoxical". It is often the case in English that a Romance loan is considerably more high-brow than its Germanic synonym ("wisdom" in this case). (I'm not a native speaker either, though.)