The most common and most likely answer to this crossword clue is the 11 letter word RISK-AVERSE
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Buddy explains!
The straight part
We know that "not adventurous" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not adventurous = risk-averse.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 RISK-AVERSE mean?
RISK-AVERSE adjective- Unwilling to take risks; especially reluctant to accept a bargain with an uncertain payoff rather than another bargain with a more certain, but possibly lower, expected payoff.