Ausência vs. falta
While both words relate to someone not being present, ausência refers to the formal state or duration of being away. Falta refers to specific instances of missing an obligation (like work or school) or the emotional feeling of missing someone.
Ausência
B1This word describes the factual state or condition of not being present. It is often used in formal, professional, or legal contexts to describe a period during which someone is away.
A ausência do diretor foi notada durante a conferência.
(The director's absence was noticed during the conference.)
Durante a minha ausência, por favor, entrem em contato com a minha secretária.
(During my absence, please contact my secretary.)
Ela tentou justificar a sua ausência prolongada do trabalho.
(She tried to justify her prolonged absence from work.)
O pai foi criticado pela constante ausência na vida dos filhos.
(The father was criticized for his constant absence in his children's lives.)
Falta
A2This word usually refers to a specific count of missed attendance (at school or work) or the emotional void felt when a person is not around (used in the phrase sentir falta).
O aluno teve três faltas na aula de história.
(The student had three absences in history class.)
Sinto muita falta da minha avó que mora longe.
(I miss my grandmother who lives far away very much.)
O chefe não aceitou a justificativa para a falta dele.
(The boss did not accept the justification for his absence.)
Você faz muita falta no nosso time.
(You are greatly missed in our team.)
Summary
Use ausência for the general, often formal, status of being away. Use falta when counting specific missed days at an institution or when expressing that you emotionally miss someone.