Smell A Rat Meaning
(idiomatic) To sense something suspicious.
Example: 1663, John Dryden, The Wild Gallant: A Comedy, act 4, scene 1:
Oh, are you thereabouts, sir? then I smell a rat, iâ€™faith; but I'll say nothing.
1874, Anthony Trollope, Phineas Redux, ch. 40:
Mr. Gresham, when he heard this, thought that he began to smell a rat, and was determined to be on his guard.