caution (n.) Look up caution at Dictionary.com
c.1300, "bail, guarantee, pledge," from Old French caution "security, surety" (13c.), from Latin cautionem (nominative cautio) "caution, care, foresight, precaution," noun of action from past participle stem of cavere "to be on one's guard" (see caveat). The Latin sense re-emerged in English 16c.-17c. Meaning "word of warning" is from c.1600.
caution (v.) Look up caution at Dictionary.com
"to warn," 1640s, from caution (n.). Related: Cautioned; cautioning.