Clue: Nude dancing clubs entertained one popularly sitting in the corner (5)
Answer: DUNCE
Explanation: Definition: one popularly sitting in the corner
 **Anagram of**(… dancing) NUDE **containing**(… entertained) C(abbrev. for "clubs", the suit in a deck of p laying cards).
Defn: Formerly, one considered disruptive or slow in learning and who was therefore punished by having to stand in a corner of the classroom.
And the eponymous headwear that goes with it: