etymologeek.com dictionary
English word beware comes from English ware, English besmirch.

Beware etymology history?

Beware detailed word origin explanation

Dictionary entryLanguageDefinition
ware English (eng) (obsolete) wary; cautious (poetic) aware (obsolete) To protect or guard (especially oneself); to be on guard, be wary.. (obsolete, _, or, _, dialectal) To be ware or mindful of something. Old eye dialect spelling of were (obsolete) The state of being aware; heed. (obsolete, UK, dialect) seaweed (nautical) To wear, or veer. (Ireland) Crockery. (countable, archaeology) A style or genre of [...]
besmirch English (eng) (transitive) To tarnish something, especially someone's reputation; to debase.. (transitive, literary) To make dirty; to soil.
beware English (eng) (defective, ambitransitive) To use caution, pay attention to (used both with and without of).

Words with the same origin as beware

Descendants of ware
wary