The flippant and universalizing way several of the commenters here are referring to money laundering as "concealing where the money came from" cast far too wide a net.
The definition you're using here would include concealing where $500 came from that was donated by anonymous friends to give to another friend in need. Suddenly, by your metric, if any of the friends suspected of donating the cash to help someone don't fess up to the source of the cash, they're laundering money.
Yeah, that's ridiculous. But it fits your description. Money laundering requires the currency be earnings from criminal activity.