Indefinite adjectives decline like nouns of the I declension (masculine) and the IV declension (feminine). An adjective always uses these two patterns — no matter which declension its noun belongs to — so a single set of endings fits every noun. The example below uses labs / laba (good).
Indefinite form
| Case | Sg. m. | Sg. f. | Pl. m. | Pl. f. |
|---|---|---|---|---|
| Nominatīvs | labs | laba | labi | labas |
| Ģenitīvs | laba | labas | labu | labu |
| Datīvs | labam | labai | labiem | labām |
| Akuzatīvs | labu | labu | labus | labas |
| Instrumentālis | (ar) labu | (ar) labu | (ar) labiem | (ar) labām |
| Lokatīvs | labā | labā | labos | labās |
Adjectives whose masculine stem ends in a soft consonant take -š in the nominative (e.g. zaļš ‘green’), but are otherwise identical: zaļa, zaļam, zaļu, zaļā.
Definite adjectives have their own set of endings.
Definite form
| Case | Sg. m. | Sg. f. | Pl. m. | Pl. f. |
|---|---|---|---|---|
| Nominatīvs | labais | labā | labie | labās |
| Ģenitīvs | labā | labās | labo | labo |
| Datīvs | labajam | labajai | labajiem | labajām |
| Akuzatīvs | labo | labo | labos | labās |
| Instrumentālis | (ar) labo | (ar) labo | (ar) labajiem | (ar) labajām |
| Lokatīvs | labajā | labajā | labajos | labajās |
Agreement in a phrase
In a phrase the adjective copies the gender, number, and case of its noun. Compare masculine labs draugs (good friend) with feminine laba māja (good house).
Indefinite, singular
| Case | labs draugs | laba māja |
|---|---|---|
| Nominatīvs | labs draugs | laba māja |
| Ģenitīvs | laba drauga | labas mājas |
| Datīvs | labam draugam | labai mājai |
| Akuzatīvs | labu draugu | labu māju |
| Instrumentālis | (ar) labu draugu | (ar) labu māju |
| Lokatīvs | labā draugā | labā mājā |
Use the indefinite form for a new or general quality, and the definite form for a specific, already-known one. The definite form is also required in the superlative, after demonstrative pronouns, and in names and titles.