The most common and most likely answer to this crossword clue is the 9 letter word SELF-MADE
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The straight part
We know that "achieved success by own efforts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case achieved success by own efforts = self-made.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 SELF-MADE mean?
SELF-MADE adjective- Of a person, having achieved success by one's own efforts, with little to no support from family members and others.
- Of a thing, made by oneself instead of bought or taken over.