lagger

noun

1. One who or that which lags behind; a laggard.

   “The economic time series can be segregated into leaders, laggers and coinciders in relation to movements in aggregate economic activity.”

2. One who installs lagging.

   “In particular, Turner & Newall doggedly contested any claims from the largest high-risk group outside the scheduled factory areas — the laggers.”

3. (informal)A player who lags (has a poor or slow network connection).
4. A marker used in the game of hopscotch.

   “2015 Kathleen, Kage, and the Company, Laggers. Laggers, Dear Readers, in case you grew up ignorant of hopscotch, are the markers you use when playing the game.”

   “In the 1950s, the game was called hopscotch and the object thrown a lagger /'lagar/. Lagger is apparently related to the verb lag.”

5. (slang)A police informant.
6. (slang)A sailor.
7. (slang)A member of support staff responsible for contacting lawyers to check how a case is progressing.