secrecy n.

late 14c., "set or kept apart, hidden, concealed," from French secret, adjective use of noun, from Latin secretum "a secret, a hidden thing" (see secret (n.)). 

Secret agent is recorded by 1715; secret service is from 1737, "department of a government concerned with counterfeiting and other political and civil offenses done in secrecy;" secret police is by 1823. Secret weapon is by 1590s.

suffix used in forming abstract nouns from adjectives (such as safety, surety), Middle English -tie, -te, from Old French -te (Modern French -té), from Latin -tatem (nominative -tas, genitive -tatis), cognate with Greek -tes, Sanskrit -tati-. Also see -ity.

late 14c., primacie, "preeminent position, supremacy, condition of being first in order, power, or importance," from Old French primacie (14c.; Modern French primatie) and directly from Medieval Latin primatia "office of a church primate" (12c.), from Late Latin primas (genitive primatis) "principal, chief, of the first rank," from primus "first" (see prime (adj.)).