Another user posted this question, and didn't get a helpful response.
"The suggested words on the top row of the Samsung keyboard can be deleted by long pressing the word which you want to delete from the dictionary (learned words).
This does not work for the leftmost word though (bug), and only works for the second word and on."
I accidentally saved a misspelled word, and I am having the same issue. How do I remove a word from my user/custom dictionary? Where is the dictionary now?