Secret
late Middle English: from Old French, from Latin secretus (adjective) ‘separate, set apart’, from the verb secernere, from se- ‘apart’ + cernere ‘sift’.
wiktionary
From Middle English secrette, from Old French secret, from Latin sēcrētus(“separated, hidden”), from ptp of sēcernō(“separate, to set aside, sunder out”), from Latin cernō [1], from Proto-Indo-European *krey- [2] [3]. Displaced Old English dēagol(“secret”) and dēagolnes(“a secret”).
etymonline
secret (n.)
late 14c., from Latin secretus "set apart, withdrawn; hidden, concealed, private," past participle of secernere "to set apart, part, divide; exclude," from se- "without, apart," properly "on one's own" (see se-) + cernere "separate" (from PIE root *krei- "to sieve," thus "discriminate, distinguish").
As an adjective from late 14c., from French secret, adjective use of noun. Open secret is from 1828. Secret agent first recorded 1715; secret service is from 1737; secret weapon is from 1936.
secret (v.)
"to keep secret" (described in OED as "obsolete"), 1590s, from secret (n.). Related: Secreted; secreting.
