fastest

1. 1
   adjective

   Superlative of fast.

   The cheetah is the fastest land animal alive today.

   Engineers built the fastest processor the company had ever shipped.

   Note

   The speed superlative, which also builds compound adjectives: one of the world's fastest-melting glaciers, hyphenated before the noun it describes. It usually comes after the or a possessive (the fastest route, the world's fastest), and record-keeping allows a new fastest time. The same spelling is also the archaic 'thou fastest', a form of the verb meaning to abstain from food, with no connection to speed.

2. 2
   adverb

   Superlative of fast.

   The new model accelerates fastest from a standing start.

   Light travels fastest through a vacuum.

   Note

   Here the superlative measures an action rather than a thing, so it follows the verb: light travels fastest through a vacuum, the model accelerates fastest from a standing start. Unlike the adjective, it often appears without the. A prepositional phrase or clause frequently says where or when the speed peaks, as in fastest through a vacuum or fastest from a standing start.

3. 3
   verbarchaic

   Second-person singular simple present indicative of fast. Archaic, used with thou.

   Note

   The -est ending that older English attached to verbs after thou, as in "when thou fastest, anoint thine head." It belongs to the religious verb meaning to go without food. Use it only to quote or imitate archaic, scriptural English. With modern you, the form is simply fast.

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