i Register
In some senses, secern is marked as archaic, literary, rare. Watch for register when choosing this word.
verb
To separate or set apart (someone or something from other persons or things).
'[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.
Often a prize would be awarded to some one dancer who had excelled his fellows. There were, I suppose, "born" Morris-dancers. Now and again one of them, flushed with triumph, would secern himself from his troupe, and would "star" round the country for his livelihood.
To separate (something from other things) in the mind; to discriminate, to distinguish.
Synonym of secrete (“to extract or separate (a substance) from the blood, etc., for excretion or for the fulfilling of a physiological function”).
[T]he joint-glands themſelves grovv rigid, and ſecern leſs of their proper humour. Hence vvhen the gout falls upon people in years, it proves very ſevere, for vvant of a neceſſary quantity of that oleaginous matter to extinguiſh it.
A friend of mine, vvhen he vvas painfully fatigued by riding on horſeback, vvas accuſtomed to call up ideas into his mind, vvhich uſed to excite his anger or indignation, and thus for a time at leaſt relieved the pain of fatigue. By this temporary inſanity, the effect of the voluntary povver upon the vvhole of his ſyſtem was increaſed; as in the caſes of dropſy above mentioned, it vvould appear, that the increaſed action of the voluntary faculty of the ſenſorium affected the abſorbent ſyſtem, as vvell as the ſecerning one.
Of a person or thing: to become separated from others.
To secrete a substance.
[…] Birds bee commonly better Meat than Beaſts, becauſe their Fleſh doth aſſimilate more finely, and ſecerneth more ſubtilly.