Asexuality is a sexual orientation. Asexual people generally do not have sexual attraction towards anyone, no matter what gender they are. Asexual people may still feel different kinds of love for others, masturbate or enjoy sex, but generally don't experience sexual attraction. Asexuality is different to not having sex for social reasons (celibacy).
Asexuality is described as a spectrum. Demisexual people are on the asexual spectrum. They experience sexual attraction, but only to people who they feel an emotional connection to. About 1% of people self-identify as asexual. Most people self-identify as heterosexual. Some self-identify as homosexual or bisexual. Some people who are antisexual may be asexual. Grey-asexual people are people who feel like they are not asexual, but they're not sexual either. For example, a grey-asexual person could experience sexual attraction very rarely. Some asexuals also identify with a romantic spectrum as well. Meaning they may feel the need to form relationships or have romantic attraction, while others may not. Some asexual people identify as queer. However, some people think that 'queer' is not an appropriate word for asexual people.