secern
To separate or set apart (someone or something from other persons or things).
archaic, literary, transitive
'[T]is not ſo much a local and bodily ſecerning our ſelves from evil men that God requires (as the Donatiſts falſely taught) but a ſpiritual ſeparation in mind and affections, and from their ſins, more than from their perſons.
To separate (something from other things) in the mind; to discriminate, to distinguish.
literary, transitive
Of a person or thing: to become separated from others.
intransitive, literary
To secrete a substance.
intransitive, literary, rare
[…] Birds bee commonly better Meat than Beaſts, becauſe their Fleſh doth aſſimilate more finely, and ſecerneth more ſubtilly.
Where it comes from
Learned borrowing from Latin sēcernere, the present active infinitive of sēcernō (“to put apart, divide, separate, sever, sunder; (figuratively) to disjoin, dissociate, part; to discern, distinguish; to exclude, pull aside, set aside, reject”), from sē- (prefix meaning ‘apart; aside; away’) + cernō (“to divide, separate; to distinguish, sift; to perceive, see; to comprehend, discern, regard, understand; to decide”) (ultimately from Proto-Indo-European *krey- (“to divide, separate, sift”)). Senses 1.3 and 2.2 (“synonym of secrete”) derive from the use of the Latin word sēcernere to translate Ancient Greek ἀποκρίνειν (apokrínein), the active infinitive participle of ἀποκρίνω (apokrínō, “to set apart, separate; to choose; to reject on inquiry; to answer, reply”).
Adapted from the Wiktionary entry secern (CC BY-SA 4.0).