The most common and most likely answer to this crossword clue is the 5 letter word PSYCH
P
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H
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The straight part
We know that "A course, in short" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a course, in short = psych.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PSYCH mean?
PSYCH noun- Psychology or psychiatry.
- A psychologist; a psychiatrist.
- To put (someone) into a required psychological frame of mind (also psych up).
- To intimidate (someone) emotionally or using psychology (also psych out).
- To treat (someone) using psychoanalysis.
- Psychedelic.
- Psychiatric.
- Indicating that one's preceding statement was false and that one has successfully fooled one's interlocutor. Also sike.
- An interjection of surprised happiness.