False lead embarrassed Hercule, initially getting it wrong (3,7)
I believe the answer is:
red herring
'false lead' is the definition.
(a red herring is a false clue)
'embarrassed hercule initially getting it wrong' is the wordplay.
'embarrassed' becomes 'red' (someone may blush or go red when embarrassed).
'initially' says to take the initial letters.
'getting it wrong' becomes 'erring' (to err is to stray or go wrong).
The first letter of 'hercule' is 'h'.
'red'+'h'+'erring'='RED HERRING'
(Other definitions for red herring that I've seen before include "Misleading clue" , "What distracts" , "food?" , "bait, of a certain sort" , "fish" .)