The meaning of caveat in Oxford Dictionaries is "warning or proviso of specific stipulations, conditions, or limitations.""
In Etymology Dictionary "warning, hint of caution," 1550s, Latin, literally "let him beware," 3rd person singular present subjunctive of cavere "to beware, take heed, watch, guard against," from PIE root *keu- "to see, observe, perceive." Legal sense "public warning preventing some action" is from 1650s.
Mid 16th century: from Latin, literally ‘let a person beware’.
There's no literal similarity from its origin,how to understand literally?