Tierney wouldn't know a gag unless it hit him right in the face.
3 seconds sound clip from the The Big Heat (1953) movie soundboard.
You can hear this line at 00:59:57.464 in the Blu-ray version of the movie.
Quote context
[...]
- With elections this close, I can't afford trouble with a crazy ex-cop.
- He's not so crazy. Got a hot flash for you. He hates your guts.
- I was there, remember? I'm the girl you left at the bar.
- I phoned The Retreat. Tierney said you offered to buy Bannion a drink.
- Tierney wouldn't know a gag unless it hit him right in the face.
- He said you followed Bannion outside.
- I went out looking for you. You made better time getting away than they make in the Olympics.
- That's a real pretty kisser.
- I thought maybe you and Bannion played footsie while my back was turned.
- You ought to trade Tierney in, get yourself a more reliable stool pigeon.
[...]