He'll be prepared to do a good deed (5)

I believe the answer is:

scout

I'm a little stuck... Click here to teach me more about this clue!

'do a good deed' is the definition.
'scout' can be an answer for 'do' (thesaurus). I'm unsure of the 'a good deed' bit.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for scout that I've seen before include "One making recce" , "Member of a youth movement" , "One searches for and recruits talented people" , "Explore" , "Member of organisation for boys" .)

I've seen this clue in the Evening Standard.

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