Good day.
While using my JVC 10U, with NO external mic, i was a bit to far away from the subject and while at this trade show, picked up a bit too much background noice from the crowd.
Is there anyway to lessen this background noice?

Thanks tons everyone.
Tom

Generally not. This is why you should virtually never use the built in mic on a camera.
You can try, but it's generally impossible. Try reducing noise by using a closing noise gate.
One thing that can be done if you have enough ambient/room audio, is to find enough length of room audio where there is no primary subject speaking/singing/whatever. Copy it, or save as a separate file(s) Use a gate or envelope in your NLE to reduce the noise between speaking. Pan the primary file slightly to one side or the other. Then paste the noise file in between those sections, with two copies panned mostly right/left. This doesn't reduce anything, but it helps the ear to focus more on the primary subject due to the shift in noise centering.