double-quick

Short definition from Wiktionary

Noun

1. 1
   The double time, a marching cadence (pace) approaching running speed.

Verb

1. 1
   To double-time, march (or rather run) at the above speedy pace.

Adverb

1. 1
   Very quickly; at once; on the double.

Adjective

1. 1
   Very quick; often used in the phrase in double-quick time.