He glanced at me in a way that might or might not have been deliberate.
Tips
history
From 《世说新语·文学》: a reply that the new fu lies 正在有意无意之间, 'precisely between intention and non-intention.' Originally an aesthetic principle, now generalized to any ambiguous action.
usage
Typically adverbial (有意无意地 + verb). Describes actions where the speaker can't or won't say whether the agent meant it, deniable but suspicious.
