Lunte riechen
Lunte riechen (pr. LOON-tuh REE-shen, Lunte gerochen (PST), LOON-tuh guh-ROH-khen; German idiom, lit. “to smell slow match”), to perceive the smell of burning slow match, which in the 16th and 17th centuries indicated the dangerous proximity of a matchlock firearm. He smelled slow match; i.e., he noticed the trap, the impending ambush, just in time and avoided it.
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909