英语词源字典 - 在线词源网站

dogged (adj.)[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]
slog (v.): 1824, "hit hard," probably a variant of slug (v.3) "to strike." Sense of "walk doggedly" first recorded 1872. Related: Slogged; slogger; slogging.
soldier (v.): "to serve as a soldier," 1640s, from soldier (n.). Related: Soldiered; soldiering. To soldier on "persist doggedly" is attested from 1954.