Vulgar programme on the radio (6)

I believe the answer is:

coarse

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'vulgar' is the definition.
(I know that vulgar can be written as coarse)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for coarse that I've seen before include "Rough-hewn" , "Rude, base" , "Rough in texture, or vulgar" , "Rough or crude, lacking refinement" , "gross" .)

I've seen this clue in The Telegraph.

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