i-adjective
secretive; mysterious; hush-hush
Colloquial adjective describing a person, behavior, or situation that seems deliberately secretive or gives off a mysterious, hush-hush vibe.
彼は最近なんだか秘密っぽいんだよね。
He's been kind of secretive lately, you know.
秘密っぽい話し方をするから、何か隠してるのかな
He talks in such a secretive way, I wonder if he's hiding something.