Crossword Genius

Is unusually hard on the outside but edible (6)

Ross

I believe the answer is:

radish

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(Other definitions for radish that I've seen before include "Hard vegetable" , "Sir had this vegetable" , "Root vegetable used in salads" , "Red cold salad ingredient" , "Bit of salad" .)

I've seen this clue in The Globe and Mail.
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