1. to leave out , to skip (In the sense of skipping an item in a sequence. Also used for skipping bits of information in a narration.)
Opposite (closest): anlassen
2. to go on about ("sich+Acc auslassen über" - usually in context of a friend going on a little rant about something.)
3. to render (For butter and fat. ONLY for cooking. I don't really know what it is to be honest.)
4. to leave out, off (In the sense of not turning on a device.)