Discourage Morse creator missing dash dot dot dash? (5)

I believe the answer is:

deter

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'discourage' is the definition.
(I know that discourage can be written as deter)

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for deter that I've seen before include "Discourage or prevent from doing something" , "Inhibit" , "Discourage (someone from an action)" , "Put off (from an action)" , "Discourage (an activity)" .)

I've seen this clue in The Telegraph.

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