Synonyms for Lag:

adj.

slack (adjective)
sluggishness, delay, pulling back, falling behind, belatedness, drag, interval, tardiness.

n.

boiler, convector, air conditioning, central heating, air-conditioned, burner, dehumidifier, air conditioner, air, ac. loiter, amble, walk, trek, step, stroll, wander, procrastinate, drag, fast, stray, saunter, hike, poke, dilly-dally, stride, tarry, delay. fizzle, backfire, set-back, time, hold up, slow, hang up, founder, crash, detain, languish, help, fail, flop, collapse, miss, stall, bomb. intermission, break, cooling-off period, recess, pause, halt, interlude, interruption. act (noun)
retardation, slowdown.
lag (noun)
imprison, fall back, retardation, jail, fall behind, interim, dawdle, jug, put away, put behind bars, slowdown, gaol, immure, incarcerate, stave, remand.

v.

follow (verb)
chase, descend, follow, result, pursue, ensue, trail, tail, succeed.
motion (verb)
dawdle, fall behind, fall back.
move slowly; delay (verb)
loiter, slow, drag, trail, dawdle, tarry, poke, procrastinate, saunter, fail, tail.

Other synonyms:

dilly-dally. detain, tarry, procrastinate. poke. drag. stall. fall behind
fall behind.
linger
loiter.
postponement
delay.
Other relevant words:
hold up, interlude, pause, collapse, put behind bars, fall back, hike, tardiness, interruption, procrastinate, remand, immure, interim, languish, time, drag, wander, belatedness, air-conditioned, bomb, amble, gaol, saunter, stray, put away, poke, imprison, dawdle, slowdown, dilly-dally, dehumidifier, stroll, jail, sluggishness, retardation, air, jug, stave, burner, loiter, flop, stall, slow, recess, fall behind, step, halt, help, fast, fail, intermission, founder, detain, incarcerate, break, crash, trek, delay, walk, convector, backfire, stride, boiler, miss, tarry, interval, fizzle.

Usage examples for lag

  1. Perhaps I may lag behind. – From Sail to Steam, Recollections of Naval Life by Captain A. T. Mahan
  2. In the same way we cannot afford to allow our insular possessions to lag behind in industrial development from any twisted jealousy of business success. – Complete State of the Union Addresses from 1790 to the Present by Various