1650s, intransitive, "to idle, waste time," perhaps a variant of daddle "to walk unsteadily." Perhaps influenced by daw, because the bird was regarded as sluggish and silly. Not in general use until c. 1775. Transitive sense in dawdle away is attested by 1768. Related: Dawdled; dawdling; dawdler.
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Definitions of dawdling from WordNet
the deliberate act of delaying and playing instead of working;