A lessened interest in or desire for sexual encounters caused by, among other things, stress, relationship troubles, depression, medication, or aging.
Example: A man has been depressed for two months. He and his partner used to enjoy sex almost daily, but now they are having sexual encounters less than once a week.
Grinnell, R. (2008). Decreased Libido. Psych Central. Retrieved on February 13, 2016, from http://psychcentral.com/encyclopedia/decreased-libido/