Suspicious, doubtful, or wary of something because you think something might be wrong.
Possibly from Dutch 'loerig' (sly) or related to 'leer' (the nautical term for turning). Etymology is uncertain but appeared in English by the 1600s meaning suspicious.
Being 'leery' used to be naval slang, possibly from Dutch sailors in trading ports—it shows how port cities mixed languages together, creating hybrid English words that survive centuries.
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