In Anthony Kenny's translation of Aristotle's Eudemian Ethics, Book II, Chapter 1 I noticed the clause
in sleep the soul is not active but idling.
I think of idling as something that an automobile motor does at traffic lights. The OED shows that the verb "to idle" was in use long before it was applied to motors, in "idle over". Still, having driven a lot, it is hard for me to separate "idling" from the automotive sense. I think of The Waste Land, the violet hour when "the human engine waits/Like a taxi, throbbing, waiting." (I think that mechanics might call the throbbing a rough idle and prescribe some adjustments.)
The Perseus Project shows that the word that Kenny renders as "idling" is "ἀργία", which Liddell and Scott do give as "idle". I suppose that "idling" is preferable here to "idle", as implying that the sleeping soul is doing something, for example dreaming.