This is the 105th most frequent Spanish word.
aún
"Still" or "yet," depending on context.
In this context, 'aún' is used in the phrase 'aún así' which is equivalent to 'even so', indicating concession or persistence despite a situation.
Aún así, decidió seguir adelante con el proyecto.
Even so, he decided to move forward with the project.
Here, 'aún' is used as a synonym of 'todavía' meaning 'yet' to indicate an action that has not been completed as of the time of speaking.
Aún no he terminado mi tarea.
I have not yet finished my homework.
Here, 'aún' means 'even', denoting an increase in degree or intensity for 'más cerca' (closer).