Hit-man's name for the letter B! (5)

I believe the answer is:

bravo

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'letter b' is the definition.
'bravo' can be an answer for 'letter' (NATO phonetic alphabet). I am not sure about the 'b' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for bravo that I've seen before include "Hurrah!" , "How broadcaster might begin birthday" , "Expression of approval" , "B in radio communications" , "Cry of approval" .)

I've seen this clue in the Evening Standard.

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