Certifiably

Part of speech: adverb

Definitions

1. In a fashion that allows for verification of authenticity or eligibility for approval
2. Done in a way that proves official authorization or qualification is met
3. Performed so that the truth or validity can be officially recognized and guaranteed

Etymology: Certifiably is a plain stacking of suffixes onto an old verb. It begins with "certify," which came into English from Old French "certifier," itself drawn from Latin "certificare," meaning "to make certain." The adjective "certifiable" grew from that verb by adding "-able," a suffix meaning "capable of being," so something certifiable is something that can be officially certified. The final ending is "-ly," which turns the adjective into an adverb. That ending descends from Old English "-līċe," which in turn came from a Germanic base meaning "body" or "form," so the older sense was roughly "in the form of" or "in the manner of." Over time "-ly" became the regular way to make adverbs from adjectives in English. Certifiably therefore means "in a manner that has been officially proven," and in everyday speech it is often used to mean "demonstrably" or "unmistakably," as in "certifiably insane."