Mental and emotional receptiveness to sexual activity. Other names for libido include sex drive, sexual receptivity, and sexual appetite.

Libido is entirely subjective, but an extremely low sex drive (for example, when a person does not want to have sex for months at a time) be a symptom of an underlying mental or physical health issue. Factors that can affect a person’s libido include age, physical and mental health, hormonal production, and diet.

Libido should not be confused with physical preparedness–e.g., erectile ability in men or vaginal fluid production in women. A person can have a strong libido, yet encounter physiological issues when attempting to have sex.