cluck (n.) Look up cluck at Dictionary.com
1703, "sound made by a hen," from cluck (v.). Slang meaning "stupid person" (turkeys are famously foolish) is from 1927.
cluck (v.) Look up cluck at Dictionary.com
Old English cloccian originally echoic. Compare Turkish culuk, one of the words for "turkey;" Greek klozein, Latin glocire, German glucken. Related: Clucked; clucking.