Crossword Genius

Costa Rican neighbour, a worker from press agency, retires completely (6)

Ross

I believe the answer is:

panama

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'costa' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for panama that I've seen before include "Canal state; hat" , "Great canal in middle America" , "Wide-brimmed hat" , "Country and straw hat" , "Canal zone" .)

I've seen this clue in the Irish Times (Crosaire) and the Irish Times.
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