Can you charge a 4.2 volt battery with a 4.6 volt charger?

Can You Charge...

Yes. As a matter of fact, in order to charge a battery, the charging voltage HAS to be greater than the charged battery's voltage or no current will flow and charging cannot happen.

Of course, the charging voltage cannot be excessive, or damage to the battery being charged will result.

In your question, 4.6 volts is not excessive for a 4.2 volt battery.