邪魔 jama = disturbance, interference, meddling, butting in
しない shinai= negative of to do
しないでください shinaide kudasai = polite form of saying: don't
しないで shinaide = shortened, colloquial version of the above
That is what one says to someone who tries to meddle, interfere, disturb, be a general nuisance.
In English, we'd tell someone like that off in ways like:
Get off my back!
That's none of your business!
Leave us/me/him/her/them alone!
(you get the drift)