Achievements, skills, or knowledge that a person has successfully acquired or accomplished.
From 'attain' plus the suffix '-ment,' which converts verbs to nouns denoting the result of an action. 'Attainments' has been used since medieval times to describe accomplishments or acquisitions.
The plural 'attainments' has a slightly old-fashioned, formal feel—you see it in Victorian novels describing a young woman's 'accomplishments and attainments,' but modern English would probably just say 'skills' or 'achievements,' showing how word choices change with social register.
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