belabor (v.)youdaoicibaDictYouDict[belabor 词源字典]
1590s, "to exert one's strength upon," from be- + labor (v.). But figurative sense of "assail with words" is attested somewhat earlier (1590s); and belabored is attested from mid-15c. with a sense of "tilled, cultivated."[belabor etymology, belabor origin, 英语词源]