Fidel Castro has finally exited stage right, after an extraordinarily long stint influencing the destiny of his country, Cuba. I was never the greatest fan, despite the good press he received for developing health and education in the country. My visit there in 2002 confirmed that however good your living standards are (which of course they were not for most people), nothing has the same value without at least the majority of freedoms. His rule definitely became an ego-trip and a cling to power in recent decades. Sad.
I don’t expect that in English speaking countries these days there are many children being named Fidel, though maybe there were one or two during the cold war. And the word fidel does not exist as a noun or adjective.
But we do have infidel. I see that this is labelled as offensive in several dictionaries and refers to an insult traded between Christians and Muslims. Didn’t realise it was still so strong!
And we have fidelity and infidelity which relate to marriage and relationships; a more formal way of saying whether you are faithful or not.
There is one further use of the term which relates to an exact copy of something. Like a copy of a work of art or a document. That leads us in turn to hi-fi which stands for high-fidelity and describes sound systems and the like which reproduce the original music, etc to a very precise degree or high level of quality.
So, not many Fidels in English but there is Fido, a popular name for dogs and name of dog food in some places. I bet you couldn’t buy that in Cuba.