Crossword Genius

Smart Alec's brother? One is irritatingly knowledgeable (6,4)

Ross

I believe the answer is:

clever dick

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

'brother? one is irritatingly knowledgeable' is the definition.
I can't judge whether this definition defines the answer.

'smart alec's' is the wordplay.
'smart' becomes 'clever' (similar in meaning).
'alec's' becomes 'dick' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'clever'+'dick'='CLEVER DICK'

Can you help me to learn more?

(Other definitions for clever dick that I've seen before include "The one with all the answers" , "Wise guy" , "Know-all" .)

I've seen this clue in The Telegraph.
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