1560s, "zealous, eager to serve," from Latin officiosus "full of courtesy, dutiful, obliging," from officium "duty, service" (see office). Sense of "meddlesome, doing more than is asked or required" had emerged by 1600 (in officiously). An officious lie (1570s) is one told to do good to another person (from Latin mendocium officiosum or French mensonge officieux). Related: Officiousness.
