Discreet is the superlative of discrete. So says the person that she is very discreet, prudent or acting tactfully. Other examples would be: sencilla-sencillisima, amable-amabilisima, etc.
discreet: refers in its verbal form as: prudentisima, reservadisima, moderate, sensatisima, mesuradisima, comedidisima.
It is said person that driving with much discretion in their actions or conduct