Translation of Herausforderer

I hope my explanation was also clear that would say that for english verbs a to needs to be put from the selection list. Like: inhale would be 'to inhale' == 'inhalar'. The 'to' is taken from a selection list.
Just last week a friend of mine showed me how to do these special effect, so I was focused about this word. I have been sleeping five hours a night for a week now and I am pretty tired all the time. Hopefully recovery will come soon.
I can already speak a little English but not too well. So I'm more cautious about making mistakes. I want to improve my English, because it is also good for your confidence and communication skills.