The definition of erratic is something that is not consistent or is lacking in a fixed course.(adjective)
A mental patient who behaves in a wildly unpredictable manner, happy and kind one minute and angry and shouting the next, is an example of someone witherratic behavior.
See erratic in Webster's New World College Dictionary
Origin: ME erratik < OFr erratique < L erraticus, wandering < pp. of errare: see err
See erratic in American Heritage Dictionary 4
Origin: Middle English erratik
Origin: , from Old French erratique
Origin: , from Latin errāticus
Origin: , from errāre, to wander; see ers- in Indo-European roots.
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