Question

what is the irony in the phrase "above board" in the story, "A Shady Plot"

Answer 1

the board is made of iron

Answer 2

first the term above board means ''legitimate, honest, and open''

That the above phrase signifies that john had faced Helen the ghost above the board and there is nothing to be hide out from his wife and there were no flirtation with the ghost which was thought by her wife he proves his wife that he had no affair with the ghost

all the best!!!