The term 'Cockatoo Topper' is a job description for someone who wears a CREST, which is a five-letter word. A cockatoo topper is a person who wears a CREST on their head, usually as part of a uniform or costume. The CREST is often made of metal and is usually decorated with symbols or designs that represent the wearer's organization or team. The CREST is usually worn on the top of the head, hence the name 'cockatoo topper'.