smell a rat แปลว่า

"Oh, Are you thereabouts, Sir; then I ſmell a Rat Ifaith; but I'll ſay nothing."

"[O]ur conjectures were like arrows ſhot in the dark—they were wide of the mark—till an old gentleman came into the room, who after affixing his ſpectacles on the ſuperior part of an aquiline noſe, told us—"he ſmelt a rat!" / "He ſmelt a rat!" and ſhaking his head with all the ſolemnity of Attic ſagacity—whiſpered to the perſon next his elbow, / "I know it!""

"Mr. Gresham, when he heard this, thought that he began to smell a rat, and was determined to be on his guard."