The word akusala often is translated into English as "evil." However, it doesn't mean what most English-speakers usually mean by "evil."
Akusala refers to acts that are karmically unwholesome and that carry the seeds of future suffering. In particular, it refers to the "unwholesome root" or "three poisons," which are greed, hate and delusion. However, anything that is a hindrance to realization of enlightenment, such as laziness or mental agitation, are akusala.
For more explanation of akusala, see "Evil, Karma and Buddhism."