1. to have a conversation, to talk ("sich+Acc unterhalten mit" - quite common. The "mit" is optional)
2. to sustain, to maintain (In the sense of financially sustain someone or something. Sounds quite formal. The noun "der Unterhalt" is used in the context of child support.)
3. to entertain ("jemanden unterhalten" - in the sense of entertainment. It's what a Netflix series does, for example. Also used reflexively in the sense of having fun somewhere.Sounds a bit "high brow", so not a good fit for a wild party. NOT for entertaining a thought.)
