§121. Case-Forms of Consonant Stems

In adjectives of Consonant stems—

a. The Ablative Singular commonly ends in -ī, but sometimes -e.

• Adjectives used as nouns (as superstes, survivor) have -e.

• Participles in -ns used as such (especially in the ablative absolute, § 419), or as nouns, regularly have -e; but participles used as adjectives have regularly -ī:—

  • dominō imperante, at the master's command; ab amante, by a lover; ab amanti muliere, by a loving woman.
• The following have regularly -ī:—āmēns, anceps, concors (and other compounds of cor), cōnsors (but as a substantive, -e),dēgener, hebes, ingēns, inops, memor (and compounds), pār (in prose), perpes, praeceps, praepes, teres.
• The following have regularly -e: caeles, compos, [†dēses],dīves, hospes, particeps, pauper, prīnceps, sōspes, superstes. So also patrials (see § 71. 5) and stems in āt-, īt-, nt-, rt-, when used as nouns, and sometimes when used as adjectives.

b. The Genitive Plural ends commonly in -ium, but has -um in the following:¹—

• Always in compos, dīves, inops, particeps, praepes, prīnceps, supplex, and compounds of nouns which have -um: as, quadru-pēs, bi-color.
• Sometimes, in poetry, in participles in -ns: as, silentum concilium, a council of the silent shades (Aen. 6.432).

c. The Accusative Plural regularly ends in -īs, but comparatives commonly have -ēs.

d. Vetus (gen. -ĕris) and pūbes (gen. -ĕris) regularly have -e in the ablative singular, -a in the nominative and accusative plural, and -um in the genitive plural. For ūber, see § 119.

e. A few adjectives of one termination, used as nouns, have a feminine form in -a: as, clienta, hospita, with the appellative Iūnō Sōspita.