usually nonphotosynthetic free-living protozoan with whiplike appendages; some pathogens of humans and other animals whip; "The religious fanatics flagellated themselves"
[ 'fla-j&-"lAt ] (transitive verb.) circa 1623. Latin flagellatus, past participle of flagellare, from flagellum, diminutive of flagrum whip; perhaps akin to Old Norse blaka to wave.