Baretti: A dictionary of the English and Italian languages
Sicúro, s. m. security, safety. Andare in sul —, al —, to go without fear. Porre, mettere in —, to secure. Stare al —, to run no risk. Al —, securely. Di —, certainly, surely.
Florio: a worlde of wordes, or most copious, dictionarie in Italian and English
sicuro: sure, secure, assured, certaine, sicker. Also safe, fast, out of danger, in safety. Also carlesnesse, negligence, Also bould, daring and searelesse.