Lesson 5: Adjective Agreement (1st–2nd Declension)

Learn how Latin adjectives agree with nouns in gender, case, and number using the bonus/bona/bonum model.

latinnovicelesson

The Agreement Rule

Latin adjectives must agree with their noun in three features:

  1. Gender (masculine / feminine / neuter)
  2. Case (nominative, genitive, dative, accusative, ablative, vocative)
  3. Number (singular / plural)

Crucially, agreement does not mean the adjective uses the same declension as the noun. A masculine noun of the 1st declension (nauta) paired with an adjective will take the masculine form of the adjective, which uses 2nd-declension endings — not 1st-declension endings.

1st–2nd Declension Adjective Model: bonus, bona, bonum

This is the most common adjective type. The masculine uses 2nd-declension endings (servus type), the feminine uses 1st-declension endings (puella type), and the neuter uses 2nd-declension neuter endings (bellum type).

Singular

Case Masculine Feminine Neuter
Nom. bonus bona bonum
Gen. bonī bonae bonī
Dat. bonō bonae bonō
Acc. bonum bonam bonum
Abl. bonō bonā bonō
Voc. bone bona bonum

Plural

Case Masculine Feminine Neuter
Nom. bonī bonae bona
Gen. bonōrum bonārum bonōrum
Dat. bonīs bonīs bonīs
Acc. bonōs bonās bona
Abl. bonīs bonīs bonīs
Voc. bonī bonae bona

Attributive vs. Predicate Adjectives

Attributive

An attributive adjective directly modifies a noun. In Latin it may come before or after the noun (the position often signals emphasis rather than grammar):

  • puella bona — the good girl (adjective after noun, neutral)
  • bona puella — the good girl (adjective before noun, slightly emphatic)

Predicate

A predicate adjective is linked to the noun by a form of esse and describes the subject:

  • Puella bona est. — The girl is good.
  • Bella magna erant. — The wars were great.

The adjective still agrees with the subject in gender, case, and number — here both nominative.

Pulcher and Other -er Adjectives

Like puer and ager, some adjectives have nominative masculine -er. Again, the genitive reveals the stem:

Adjective Gen. m. Stem Meaning
pulcher pulchrī pulchr- beautiful (drops -e-)
niger nigrī nigr- black (drops -e-)
liber liberī liber- free (keeps -e-)

Full feminine form: pulchra, pulchrae; neuter: pulchrum, pulchrī — otherwise identical to bonus.

Key Vocabulary — Adjectives

Latin (m./f./n.) Meaning
bonus / bona / bonum good
malus / mala / malum bad, evil
magnus / magna / magnum great, large
parvus / parva / parvum small
longus / longa / longum long
multus / multa / multum much, many (pl.)
pulcher / pulchra / pulchrum beautiful
niger / nigra / nigrum black
albus / alba / album white
novus / nova / novum new
antīquus / antīqua / antīquum ancient, old
Rōmānus / Rōmāna / Rōmānum Roman
Latīnus / Latīna / Latīnum Latin

Ten Example Sentences with Analysis

1. Puella bona aquam portat.

  • bona agrees with puella: fem., nom., sg.
  • Translation: The good girl carries water.

2. Servus malus agrōs nōn colit.

  • malus agrees with servus: masc., nom., sg.
  • Translation: The bad slave does not cultivate the fields.

3. Rēgīna magnam silvam amat.

  • magnam agrees with silvam: fem., acc., sg.
  • Translation: The queen loves the great forest.

4. Bella magna semper mala sunt.

  • magna agrees with bella: neut., nom., pl.; mala is predicate adjective, neut., nom., pl.
  • Translation: Great wars are always bad.

5. Puer pulcher in viā stat.

  • pulcher agrees with puer: masc., nom., sg.
  • Translation: The beautiful boy stands in the road.

6. Amīcī bonī semper verum dīcunt.

  • bonī agrees with amīcī: masc., nom., pl.
  • Translation: Good friends always speak the truth.

7. Nauta bonus insulam novam videt.

  • bonus agrees with nauta: masc. noun (1st decl.), nom., sg. → masc. adj.
  • novam agrees with insulam: fem., acc., sg.
  • Translation: The good sailor sees a new island.

8. Oppidum antiquum in colle est.

  • antīquum agrees with oppidum: neut., nom., sg.
  • Translation: The ancient town is on the hill.

9. Verba magistrī Latīnī longa sunt.

  • Latīnī agrees with magistrī: masc., gen., sg.
  • longa agrees with verba: neut., nom., pl. (predicate)
  • Translation: The words of the Latin teacher are long.

10. Fēminae Rōmānae in oppidō magnō habitant.

  • Rōmānae agrees with fēminae: fem., nom., pl.
  • magnō agrees with oppidō: neut., abl., sg. (with in)
  • Translation: The Roman women live in the great town.

Practice

A. Make the adjective agree with the noun:

  1. puella + magnus → ?
  2. servōrum + bonus → ?
  3. bella (nom. pl.) + longus → ?
  4. nautae (dat. sg.) + novus → ?
  5. vīnum + antiquus → ?

B. Translate:

  1. Magistrī bonī puerōs laudant.
  2. Silva magna et pulchra est.
  3. Multa oppida Rōmāna antiqua sunt.
  4. The good farmer loves the new field.
  5. The women carry white water. (aqua alba)

Answer key A:

  1. magna (fem., nom., sg.)
  2. bonōrum (masc., gen., pl.)
  3. longa (neut., nom., pl.)
  4. novō (masc., dat., sg.)
  5. antīquum (neut., nom./acc., sg.)

Answer key B:

  1. Good teachers praise the boys.
  2. The forest is great and beautiful.
  3. Many Roman towns are ancient.
  4. Agricola bonus agrum novum amat.
  5. Fēminae aquam albam portant.

Summary

  • Latin adjectives agree with their noun in gender, case, and number — not declension.
  • The bonus / bona / bonum model is the most common: masc. = 2nd decl., fem. = 1st decl., neut. = 2nd decl. neuter.
  • Attributive adjectives modify nouns directly; predicate adjectives describe the subject via esse.
  • For -er adjectives, check the genitive to find the stem and predict all other forms.
  • A noun from the 1st declension (nauta, masc.) still takes a masculine adjective form.