Crossword clue: a brimless dark blue scottish cap with a flat top and a plume on one side
2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
a brimless dark blue Scottish cap with a flat top and a plume on one side
a brimless dark blue Scottish cap with a flat top and a plume on one side