The most common and most likely answer to this crossword clue is the 6 letter word COWING
I've seen this crossword clue in The Times
C
O
W
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Buddy explains!

The straight part
We know that "Intimidating" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case intimidating = cowing.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 COWING mean?
COWING verb- (chiefly in the passive voice) To intimidate; to daunt the spirits or courage of.