Technically if in US you could be seen as money launder. But they don't seem to enforce this much on individuals. They go for the exchanges it seems.
It's perfectly legal for individuals to buy bitcoins from other individuals. Just like it's legal for me to meet you and sell some old newspapers, or jewelry, or whatever. The problem comes up when people start talking about anything illegal. If you meet somebody and they say anything illegal just say no thank you and call off the deal.
Also, if you're doing small amounts it's not a big deal. If you're doing high amounts, like over say $5-10K, especially if you do this repeatedly then yes that could be a concern.
Biggest time was around silk road take down they did go after people on money laundering. Look up Charlie Shrem, he did get some serious trouble for what they considered money laundering.
Charlie Shrem ran a business that exchanged bitcoins for fiat currency without proper licenses, and also when knowing they were likely to be used on the Silk Road drug marketplace. That's a no no.