By now, you know that possessive pronouns like мой (my) and ваш (your) act like adjectives, changing endings to match the gender, number, and case of the noun they modify.
However, the third-person possessives are completely indeclinable. They never change their form, regardless of the case, gender, or number of the noun they modify.
- его (his / its) — note that the г is pronounced like a в
- её (her)
- их (their)
Её (Her)
When you want to say "her," always use её. Even if the noun it modifies changes case, the pronoun её stays exactly the same.
Его (His/Its)
Similarly, его means "his" or "its". Whether modifying a masculine noun like степлер (stapler) or a feminine noun like линейка (ruler), его does not change.
Их (Their)
To say "their," use их. This form remains fixed even when referring to plural objects or locations like переговорная (meeting room).
Fixed across all cases
Notice how these pronouns remain unchanged when their nouns take on various cases—whether it's the Accusative case, the Genitive case after prepositions like около (near), or the Instrumental case.