Imperceivably

Part of speech: adverb

Definitions

1. In a way that is so minute or faint it remains undetected
2. Done so subtly that it escapes notice, often implying an imperceptible transformation
3. In a way that is so subtle or tiny it cannot be detected by the senses

Etymology: "Imperceivably" is simply "imperceivable" with the adverbial ending "-ly" added to it. The base word is built from the prefix "im-" meaning "not" attached to "perceivable," which means "able to be perceived." So the adverb describes doing something in a way that cannot be picked up by the senses, as in a change so small that no one notices it happening. The construction is a plain one: English readily turns adjectives ending in "-able" or "-ible" into adverbs by adding "-ly," and "imperceivable" follows that pattern. The word is a straightforward formation in the same way as "inevitably" or "unbelievably," so its history lies mainly in the parts it draws on rather than in any single moment of coinage.

Synonyms: subtly, unnoticeably, indiscernibly, insensibly, gradually

Antonyms: obviously, noticeably, perceptibly, clearly, evidently