dogged (adj.)youdaoicibaDictYouDict[dogged 词源字典]
"having the qualities of a dog" (mostly in a negative sense), c. 1300, from dog (n.). Meaning "persistent" is from 1779. Hence doggedly (late 14c.), "cruelly, maliciously;" later "with a dog's persistence" (1773). Related: Doggedness.[dogged etymology, dogged origin, 英语词源]