at first blush
idiom

- when you first see or experience something

Cambridge Dictionary

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WORD ORIGIN

Many words endure long and complicated journeys before taking on their current meaning. Blush is one of those. According to the Barnhart Concise Dictionary of Etymology, blush can be traced back to around 1350 and the words blissen/blishen, meaning to glance, look or stare at. About a century later it changed to blussen and then blisshen.

These Middle English forms apparently developed from 1) the Old English "blysian" (to blush), which is related to the Dutch blozen and Middle Low German blosen/bloschen and 2) the Old English blyscan (earlier bluskjan), meaning to become red or to glow. The sense of a reddening or a rosy colour of the face was first recorded at the end of the 16th century.

The origin of the full idiom at first blush in unknown. However, the earliest written record available to view online is in William Spurstowe's The Wells of Salvation Opened, from the year 1655.

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SYNONYMS

at first glance, at first sight, in the first moments

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SMUGGLE OWAD into a conversation:

"Well, AT FIRST BLUSH, he seemed like a really nice guy. However, after talking to him, I started to have doubts."