This is one of those often-used words that we think we know what it means. I think maybe Inigo Montoya disapproves when we use it too much.

“The deadpan delivery did nothing to soften the blow of the bad news.”

Deadpan – adjective

1) showing no feeling or emotion

2) marked by an impassive matter-of-fact manner, style, or expression.

~per Merriam-Webster