1. Adjectives agree with their nouns in Gender, Number, and Case:--
vir fortis [a brave man]
multus sanguis [much blood]
urbium magnarum [of great cities]
cenam optimam [the best supper]

2. To agree with two or more nouns the adjective becomes plural or follows the nearest noun:--
Caecilius et Grumio laeti sunt. [Caecilius and Grumio are happy]
Servus totam et culinam et atrium lavat. [the servant washes the whole kitchen and hall]
natura inimica sunt libera civitas et rex. [by nature a free state and a king are hostile]
multae operae ac laboris [of much trouble and toil]
vita moresque mei [my life and character]

3. A collective noun may take an adjective of the gender and number of the individuals implied :--
multitudo convicti sunt [a multitude were convicted]
magna pars raptae [a large part of the women were seized]

4. Abstract nouns may have an Adjective in the neuter plural :--
stultitia et iniustitia ... sunt fugienda [folly and injustice... are [things] to be shunned]
labor (m.) voluptasque (f.) societate naturali sunt iuncta (n.) [labor and delight are bound by natural alliance]

5. Adjectives as nouns:
masculine = people in general,
feminine = women,
neuter = things:--

meus propinquus [my neighour]
honestum [an honorable act, or virtue (as a quality)]
omnes fortia laudant [all men praise bravery (brave things)]
varium et mutabile semper femina [woman is ever a changing and fickle thing]
malum mihi videtur esse mors [death seems to me to be an evil]

6. Adjectives as nouns: with added meaning from constant association:--
Africus [ventus] [the southwest wind]
Ianuarius [mensis] [January]
vitulina [caro] [veal (calf's flesh)]
fera [bestia] [a wild beast]
patria [terra] [the fatherland]
Gallia [terra] [Gaul (the land of the Galli)]
hiberna [castra] [winter quarters]
triremis [navis] [a three-banked galley, trireme]
argentarius [faber] [a silversmith]
regia [domus] [the palace]