Allen & Greenough · Part First — Words and Forms › Defective Nouns

§103. Nouns Defective in Certain Cases

Many nouns are defective in case-forms:¹—

a. Indeclinable nouns, used only as nominative and accusative singular: fās, nefās, īnstar, nihil, opus (need), secus.

b. Nouns found in one case only (monoptotes):—

In the nominative singular: glōs (F.).
In the genitive singular: dicis, naucī (N.).
In the dative singular: dīvīsuī (M.) (cf. § 94. c).
In the accusative singular: amussim (M.); vēnum (dative vēnō in Tacitus).
In the ablative singular: pondō (N.); māne (N.); astū (M.), by craft; iussū, iniussū, nātū, and many other verbal nouns in -us (M.) (§ 94. c).
Note.—Māne is also used as an indeclinable accusative, and an old form mānī is used as ablative. Pondō with a numeral is often apparently equivalent to pounds. A nominative singular astus and a plural astūs occur rarely in later writers.
In the accusative plural: īnfitiās.

c. Nouns found in two cases only (diptotes):—

In the nominative and ablative singular: fors, forte (F.).
In the genitive and ablative singular: spontis (rare), sponte (F.).
In the accusative singular and plural: dicam, dicās (F.).
In the accusative and ablative plural: forās, forīs (F.) (cf. forēs), used as adverbs.

d. Nouns found in three cases only (triptotes):—

In the nominative, accusative, and ablative singular: impetus, -um, -ū (M.)²; luēs, -em, -ē (F.).
² The dative singular impetuī and the ablative plural impetibus occur once each.
In the nominative, accusative, and dative or ablative plural: grātēs, -ibus (F).
In the nominative, genitive, and dative or ablative plural: iūgera, -um, -ibus (N.); but iūgerum, etc., in the singular (cf. § 105. b).

e. Nouns found in four cases only (tetraptotes):—

In the genitive, dative, accusative, ablative singular: diciōnis, -ī, -em, -e (F.).

f. Nouns declined regularly in the plural, but defective in the singular:—

Nouns found in the singular, in genitive, dative, accusative, ablative: frūgis, -ī, -em, -e (F.); opis, -ī (once only), -em, -e (F.; nominative Ops as a divinity).
Nouns found in the dative, accusative, ablative: precī, -em, -e (F.).
Nouns found in the accusative and ablative: cassem, -e (F.); sordem, -e (F.).
Nouns found in the ablative only: ambāge (F.); fauce (F.); obice (C.).

g. Nouns regular in the singular, defective in the plural:—

The following neuters have in the plural the nominative and accusative only: fel ( fella), far ( farra), hordeum ( hordea), iūs, broth ( iūra), mel ( mella), murmur ( murmura), pūs ( pūra), rūs ( rūra), tūs orthūs ( tūra).
Note.—The neuter iūs, right, has only iūra in classical writers, but a very rare genitive plural iūrum occurs in old Latin.
calx, cor, cōs, crux, fax, faex, lanx,lūx, nex, ōs ( ōris),³ os ( ossis),⁴pāx, pix, rōs, sāl, sōl, vas ( vadis), want the genitive plural.
³ The ablative plural ōribus is rare, the classical idiombeing in ōre omnium, in everybody's mouth, etc., not in ōribus omnium.
⁴ The genitive plural ossium is late; ossuum (fromossua, plural of a neuter u-stem) is early and late.
Most nouns of the fifth declension want the whole or part of the plural (see § 98. a).

h. Nouns defective in both singular and plural:—

Noun found in the genitive, accusative, ablative singular; nominative, accusative, dative, ablative plural: vicis, -em, -e; -ēs, -ibus.
Noun found in the genitive, dative, accusative, and ablative singular; genitive plural wanting: dapis, -ī, -em, -e; -ēs, -ibus.

J. H. Allen and J. B. Greenough, New Latin Grammar (Boston: Ginn, 1903). Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities.