What's the difference between lucky & fortunate

What's the difference between lucky & fortunate

what can i say
hardly there is not different,but once youve put them in to a sentence...
there are many words in english that has a "same" meaning,but they are different,like lucky and fortunate or unclear and ambiguous.people dont like use a same word twice at once (thats called repetation,but sometimes we need repetation).

Lucky 是幸运的意思，运气好。
Fortunate 是运气的意思，但不含好坏。