serius

Indonesian

Borrowed from English serious and Dutch serieus, from Medieval Latin sēriōsus, an extension of Latin sērius (“grave, earnest, serious”), from Proto-Indo-European *swer- (“heavy”).

IPA^(key): (Standard, English-influenced) /sə.ˈri.ʊs/, (Dutch-influenced) /sɛ.ˈri.ʊs/
Rhymes: -ʊs, -s
Hyphenation: sê‧ri‧us

sêrius

Somewhat disputed. There are two main competing hypotheses:^[1]

Usually held to derive via Proto-Italic *swerjos from Proto-Indo-European *swer-yo-s, from the root *swer- (“heavy”). Cognate with Old English swǣr (“heavy, grave, grievous”), German schwer (“hard, difficult, heavy”), Lithuanian sverti (“to weigh, balance”), svarùs (“heavy”). More at sweer.
According to De Vaan, rather from Proto-Italic *sērjos, from Proto-Indo-European *seh₁-ro-s + *-yo-, from an uncertain root *seh₁- (“to go slowly?”) (cf. sēgnis (“slow, tardy, sluggish, lazy”)). In this case, equivalent to sērus (“slow, tardy”) +‎ -ius, with semantic shift "slow" > "tiring" > "heavy" > "grave, serious".

sērius (feminine sēria, neuter sērium); first/second-declension adjective

	masculine	feminine	neuter	masculine	feminine	neuter
	singular			plural
nominative	sērius	sēria	sērium	sēriī	sēriae	sēria
genitive	sēriī	sēriae	sēriī	sēriōrum	sēriārum	sēriōrum
dative	sēriō	sēriae	sēriō	sēriīs
accusative	sērium	sēriam	sērium	sēriōs	sēriās	sēria
ablative	sēriō	sēriā	sēriō	sēriīs
vocative	sērie	sēria	sērium	sēriī	sēriae	sēria

sērius

^ De Vaan, Michiel (2008) “sērius”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, pages 556-7

“serius”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
“serius”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
serius in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
serius in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
Carl Meißner, Henry William Auden (1894) Latin Phrase-Book‎^[1], London: Macmillan and Co.
- two days late: biduo serius
- (ambiguous) to say in earnest..: serio dicere (Plaut. Bacch. 1. 1. 42)
“serious”, in The Century Dictionary […], New York, N.Y.: The Century Co., 1911, →OCLC.