Promiscuous chap Alec heroically corners (6)

I believe the answer is:

lecher

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

'promiscuous chap' is the definition.
(I've seen this before)

'alec heroically corners' is the wordplay.
'LECHER' is hidden in amongst the letters.
But, I am unsure how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for lecher that I've seen before include "Libertine" , "Person of unrestrained sexual desires" , "Promiscuous chap" , "He's obsessed with sex" .)

I've seen this clue in The Times.

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