Does his chest look inflamed? (5)

I believe the answer is:

robin

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'does his chest look inflamed?' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.

This is all the clue.

Can you help me to learn more?

(Other definitions for robin that I've seen before include "Batman's assistant" , "Small songbird" , "Batman's companion" , "Bird; man's name" , "Friendly winter bird" .)

I've seen this clue in the Evening Standard.

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