Literally means "weak sperm". Refers to semen in which the motility (active movement of the sperm) is less than forty percent.
A lower than normal number of sperm in the ejaculate of a man
Decreasing of quantity of mobile forms and also the speed of sperm movement in the ejaculate.
Asthenozoospermia (or "asthenospermia") is the medical term for reduced sperm motility.