[THE SIMPLE SENTENCE.]
[(A.) USE OF THE NOUN.]
[NUMBER AND GENDER.]
[1099.] The singular of a word denoting a person is sometimes used in a collective sense.
This singular is generally a military designation: as, mīles, eques, pedes, hostis, Rōmānus, Poenus. But other substantives and adjectives are occasionally thus used.
[1100.] A substantive or adjective denoting a person is often used in the singular as representative of a class, particularly when two persons are contrasted: as,
sī tabulam dē naufrāgiō stultus adripuerit, extorquēbitne eam sapiēns? Off. 3, 89, if a fool has seized a plank from a wreck, will the sage twitch it away?
[1101.] The neuter singular of certain adjectives is used as an abstract substantive.
These adjectives have commonly stems in -o-, and are often used in the partitive genitive ([1250]). The nominative is rare, also the accusative and ablative, except in prepositional constructions. Such are: bonum, malum; rēctum, prāvum; decōrum, indecōrum; honestum; vērum, falsum; iūstum, iniūstum; aequum; ambiguum; rīdiculum. ūtile, ināne, commūne, īnsīgne, simile, &c.
[1102.] Certain adjectives, which originally agreed with an appellative denoting a thing, have dropped the appellative and become substantives.