If you guessed that the secret to the origins of secrete is the word secret, you are correct. Secrete developed in the mid-18th century as an alteration of a now obsolete verb secret. That verb had the meaning now carried by secrete and derived from the familiar noun secret ("something kept hidden or unexplained"). The noun, in turn, traces back to the Latin secretus, the past participle of the verb secernere, meaning "to separate" or "to distinguish." Incidentally, there is an earlier and distinct verb secrete with the more scientific meaning "to form and give off (a secretion)." That secrete is a back-formation from secretion, another word that can be traced back to secernere.