a viscous liquid, Old English teoru, teru "tar, bitumen, resin, gum," literally "the pitch of (certain kinds of) trees," from Proto-Germanic *terw- (source also of Old Norse tjara, Old Frisian tera, Middle Dutch tar, Dutch teer, German Teer), probably a derivation of *trewo-, from PIE *derw-, variant of root *deru- "be firm, solid, steadfast," with specialized senses "wood, tree" and derivatives referring to objects made of wood.
Tar baby "a sticky problem," also a derogatory term for "black person," is from an 1881 "Uncle Remus" story by Joel Chandler Harris. Tarheel for "North Carolina resident" first recorded 1864, probably from the gummy resin of pine woods. Tar water, an infusion of tar in cold water, was popular as a remedy from c. 1740 through late 18c.
also Jack Tar, "sailor," 1670s, probably a special use of tar (n.1), which stuff was a staple for waterproofing aboard old ships (sailors also being jocularly called knights of the tarbrush); or possibly a shortened form of tarpaulin, which was recorded as a nickname for a sailor in 1640s, from the tarpaulin garments they wore.
late Old English, "to smear with tar," from tar (n.1). To tar and feather (1769) was famously a mob action in America in Revolutionary times (used by both sides) and several decades thereafter. The punishment itself first is found in an ordinance of Richard I (1189) as the penalty in the Crusader navy for theft. Among other applications over the years was its use in 1623 by a bishop on "a party of incontinent friars and nuns" [OED], but the verbal phrase is not attested until 18c. Related: Tarred; tarring.