clocker

[ klok-er ]
/ ˈklɒk ər /

noun

a person who times racehorses during tryouts to determine their speed.
an official who times a race.
a person who maintains a record of the flow of traffic, as of visitors to a museum.

Origin of clocker

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for clocker