"speed-increasing gear in an automobile," 1929, from over- + drive (n.). Earlier it was a transitive verb, "to drive too hard, work to exhaustion," Old English oferdrifan.
Melissa's brain was in overdrive
Troops are ready to go into overdrive as soon as the signal is given
overdone
overdose
overdraft
overdraw
overdress
overdrive
overdub
overdue
overeat
overeducated
overestimate
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