You may say "Geh weg."

Hau Ab Verschwinde Verzieh dich Verpiss dich Zieh Leine Note that 'Fuck' is rarely directly translated. It has mainly a sexual meaning (ficken), which is rarely used in a non sexual way. Only one I can think of is 'Fick dich ins Knie' (same as 'Hau ab'). Generally, in German sexual courewords are not very common - and if you do not speak speak German very well I suggest not to use any swear words at all.