An androgynous entity is one of indeterminate sex or possessing attributes considered both male and female. Androgynous is the descriptor for androgyny and someone who is androgynous has both male and female characteristics - this is not to say specifically that the person has male and female genitalia, but that the person exhibits behaviors, emotions, or traits that are considered to be masculine or feminine.
Essentially an androgynous person is a mix of maleness and femaleness. It is actually often considered advantageous to be behaviorally androgynous and have both traditionally masculine and feminine traits - this leads to greater adaptability.
For example, imagine a father whose wife passes way leaving him with three young daughters. He would be better able to adapt to this situation if he had some traditionally 'feminine' traits such as emotionality along with cooking/cleaning skills. Concepts of androgyny evolve over time in that societal perceptions of what is considered masculine and feminine change. For example, 200 years ago it was considered uncommon for a woman to have a job. Now it is commonplace and a woman having a job isn't considered androgynous.
This can also describe physical androgyny such as individuals who look both masculine and feminine (think David Bowie) or individuals who are intersexed or are "hermaphrodites" (hyperlink?) which is considered outdated terminology at this point. Intersexed means there is a human or animal birth in which the organism has sexual organs for both genders. In humans this is often treated by surgical intervention. Sometimes surgeries occur before it is certain which sex the infant will develop into leading to situations where the "wrong" sex was chosen and children feeling as if they are the wrong biological sex. It is recommended now to delay surgical interventions for intersexed infants until it is more clear which biological sex is predominant.