Without a brother or brothers; having no male siblings.
From 'brother' plus the suffix '-less', meaning 'without' or 'lacking.' The '-less' suffix is one of English's most transparent and productive, allowing speakers to negate almost any noun.
The '-less' suffix is so productive that English speakers instantly understand 'brotherless,' 'wireless,' 'careless'—we can create hundreds of new adjectives and everyone understands them immediately, which is why English is easy to expand.
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