Kusala/Kushala:
Sanskrit - Dictionary
Normally it means "skillful", but there are many related qualities.
"Kusala and
akusala, a pair of terms coined by the Buddha, are the primary terms to evaluate human behavior and morality. Literally,
kusala can be differently rendered as skillful, intelligent, expert; good, right, virtuous, meritorious, beneficial; lucky, happy, healthy and prosperous, as the context demands.
Akusala can, therefore, be translated into English as the opposite qualities from
kusala such as unskillful, bad and so on."
http://www.buddhivihara.org/kusala-and-akusala-as-criteria-of-buddhist-ethics/