What does it mean?
Mental effluent, pollutant, or fermentation. Four qualities — sensuality, views, becoming, and ignorance — that “flow out” of the mind and create the flood of the round of death and rebirth.
-from Access to Insight
Why does it matter?
The above definition is a brave attempt at translating āsava, but I think it’s trying a little too hard. The word actually can mean either inflow or outflow, which adds another layer of complication for translators, but I think the meaning is actually quite simple. What do you immediately think of when you hear “effluent” or “outflow”? Shit, right? You think of shit? Well, you’re on the right track. Ãsava just means the gunk of your mind. All the junk that you need to get rid of to purify your system.