Aplazar vs. posponer vs. postergar

In Spanish, there are several synonyms for the English 'to postpone' or 'to put off'. These include 'aplazar', 'posponer', and 'postergar'. While they all generally mean to delay something for later, there can be subtle differences in their usage due to regional variations, formality and context. Let's look at each one individually.

Aplazar

Generally, 'aplazar' means to postpone or reschedule something for a later date or time.
Debido a la lluvia, tuvieron que aplazar el partido de fútbol.
(Due to the rain, they had to postpone the soccer match.)
Voy a aplazar la reunión hasta la próxima semana.
(I'm going to postpone the meeting until next week.)

Posponer

'Posponer' also implies delaying something to a later time. Its usage can be more formal and common in written language.
El profesor pospuso el examen hasta el lunes.
(The professor postponed the exam until Monday.)
Se ha decidido posponer la inauguración debido al mal tiempo.
(It has been decided to postpone the inauguration due to bad weather.)

Postergar

'Postergar' generally means to delay, put off, or even neglect something. It can sometimes carry a slightly negative connotation of avoiding or evading.
No debes postergar tu visita al médico.
(You should not put off your visit to the doctor.)
Siempre estás postergando tus responsabilidades.
(You are always putting off your responsibilities.)

Summary

'Aplazar', 'posponer' and 'postergar' all refer to delaying or moving something to a later date. However, their usage may vary with 'aplazar' often used in everyday conversation, 'posponer' being more formal and commonly seen in written language, and 'postergar' sometimes carrying a connotation of neglect or avoidance.