rounder (n.)youdaoicibaDictYouDict[rounder 词源字典]
1620s, "a sentinel," agent noun from round (n.) on notion of "one who makes the rounds." Sense of "chronic drunkard or criminal" is from 1854, on notion of one who is habitually in and out of jails or bars. Rounders, a baseball-like game, attested from 1828.[rounder etymology, rounder origin, 英语词源]