Loimós (λοιμός) means plague, pestilence, deadly epidemic. Figuratively, a 'pest' — a dangerous troublemaker. Both senses appear in the NT.
Jesus lists loimós among end-time signs in Luke 21:11: 'great earthquakes, famines and pestilences.' In Acts 24:5, Paul's accusers call him 'a plague' — using the word as insult. Revelation 6:8 includes pestilence among the four horsemen's instruments. The theological response to plague is not fatalism but trust in the sovereign God who promises in Psalm 91:3: 'Surely he will save you from the deadly pestilence,' combined with prayer for mercy as in Joel 1-2.