‘Read between the lines’

Meaning: Identify a meaning that isn’t made obvious

Explanation:Dating back to the 19th century, this phrase comes from a form of cryptography where a hidden meaning was secreted between lines of text. Before long it began to refer to interpreting any coded or unclear message in a range of contexts.

Example:Her email was chatty and cheerful, but reading between the lines I don’t think she’s happy there.