In a beady manner; with beady eyes or in a way that resembles beads; looking intently or suspiciously.
From beady (bead + -y) + -ly (Old English adverb suffix). The -ly transformation converts the adjective into an adverb describing manner or behavior.
Adverbs ending in -ly are so common we barely notice them, but 'beadily' shows how English systematically converts any adjective into a description of how something happens—it's one of our language's most efficient productivity mechanisms.
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