This is the 1763rd most frequent Spanish word.
santa
Saint or holy (feminine form).
In this context, 'Santa' is used as a religious title referring to 'Saint'.
La iglesia tiene una estatua de Santa María.
The church has a statue of Saint Mary.
Here, 'santa' is used as an adjective meaning 'saintly' or 'virtuous' when describing someone's behavior or character.
Mi hermana Sara siempre fue una santa con los niños.
My sister Sara was always a saint with children.
In this sentence, 'santa' is used as an attributive adjective meaning 'holy' referring to the night celebrated.