From The Collaborative International Dictionary of English v.0.48:
Lag \Lag\, v. i. [imp. & p. p. Lagged; p. pr. & vb. n.
Lagging.]
To walk or more slowly; to stay or fall behind; to linger or
loiter. "I shall not lag behind." --Milton.
Syn: To loiter; linger; saunter; delay; be tardy.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Lagging \Lag"ging\, n.
1. (Mach.) The clothing (esp., an outer, wooden covering), as
of a steam cylinder, applied to prevent the radiation of
heat; a covering of lags; -- called also deading and
cleading.
[1913 Webster]
2. Lags, collectively; narrow planks extending from one rib
to another in the centering of arches.
[1913 Webster]