flea-bite (n.)youdaoicibaDictYouDict[flea-bite 词源字典]
mid-15c., figurative, "something that causes but slight pain," from flea (n.) + bite (n.). Related: Flea-bitten (1560s); flea-biting (verbal noun), 1550s.[flea-bite etymology, flea-bite origin, 英语词源]