The redifining of language for political purposes

I googled 'fuhrer' and i got an immediate dictionary pop up result defining it as something like 'a ruthless dictator'

No, 'fuhrer' translates as 'guide'. To this day, if you have a mountain guide take you walking up a mountain in germany, they would be called a 'bergsfuhrer'.

I dont know why new definitions need making up. A word has a meaning and thats it, thats its meaning.