[*] 103. 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:
(N.); māne (N.); astū (M.), by craft;
, and many other verbal nouns in -us (M.) (§ 94.
[*] 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 .
- 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.
- In the nominative, accusative, and ablative singular: impetus, -um, -ū (M.)2; luēs , -em, -ē (F.).
- 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).
- 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.).
- 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 ).
- 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.
- Most nouns of the fifth declension want the whole or part of the plural (see § 98. a).
- 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.