1. to stop, to bring to a halt (In context of stopping a directed movement, often driving. NOT for stopping an activity (aufhören) and also not for a superhero stopping a villain (aufhalten).)
Opposite (closest): losfahren
2. to continue (Only used in a few contexts, usually for circumstances persisting. Think rain that just won't stop.)
3. to implore, to push toward doing ("jemanden anhalten zu" - not forceful. Sounds like you're trying to convince with pleas and arguments. Not very common overall.)
Opposite (closest): abhalten
4. to ask for marriage ("um jemandes Hand anhalten")
