From Longman Dictionary of Contemporary Englishjesterjest‧er /ˈdʒestə $ -ər/ noun [countable] 
BOFUNNYa man employed in the past by a ruler to entertain people with jokes, stories etc
BOFUNNYa man employed in the past by a ruler to entertain people with jokes, stories etcExamples from the Corpus
jester• He is a bit of a jester but great fun to be with.• Gatling has become a relentless court jester, mugging, leading cheers and conducting interviews.• He also saw how drained he could become after playing the court jester.• They wore the motley coat of jesters and one of them was hopping around on a hobby horse.• And the answer came: she was like a break in the monotony, like a resident jester.• Still the message remains the same whoever the messenger-the jesters are the boil lancers.• The jester in Notker's story conveys the anxiety of men at the mercy of the king's will. 