droll sense of humor

宮部みゆきの小説 "The Sleeping Dragon" を読んでいます。

"Don't worry. But you've got to tell me about anything that comes of it. Has something happened?"
I didn't respond immediately, so he clapped me on the back. "Forget about it until you've got something. Whatever it's about, it seems to be taking a toll on you."
"You can tell?"
"Your hair's going gray."
I went to the men's room to check, but it wasn't true. The old man had a droll sense of humor.
He laughed when I came out.
"Your hair's going gray." はからかって言われたのは明白です。 "droll sense of humor" の "droll" を辞書で調べます。

・Oxford English Dictionary: Curious or unusual in a way that provokes dry amusement.: No, I didn't do the chicken dance or anything so droll.

・Collins Dictionary: Something or someone that is droll is amusing or witty, sometimes in an unexpected way.: The band have a droll sense of humour.

・Cambridge English Dictionary: humorous, especially in an unusual way: I always loved his droll sense of humor.

"droll sense of humor" のフレーズで覚えた方が良さそうです。