tipster[noun]Synonyms: informer, betrayer, canary, fink, nark, snitch, squealer, stool pigeon, talebearer, tattler
 [TahlilGaran] English Synonym Dictionary ▲
 tip‧ster /ˈtɪpstə $ -ər/ 
 noun [countable] someone who gives information about which horse is likely to win a race 
 [TahlilGaran] Dictionary of Contemporary English ▲