Old English scinan "shed light, be radiant" (class I strong verb; past tense scan, past participle scinen), from Proto-Germanic *skinanan (cf. Old Saxon and Old High German skinan, Old Norse and Old Frisian skina, Dutch schijnen, German scheinen, Gothic skeinan "to shine, appear"), from PIE root *skai- "to gleam, shine, flicker" (cf. Sanskrit chaya "brilliance, luster; shadow," Greek skia "shade," Old Church Slavonic snati "to flash up, shine," Albanian he "shadow"). Transitive meaning "to black (boots)" is from 1610s. Related: Shined (in the shoe polish sense); shining.
1520s, "brightness," from shine (v.). Meaning "polish given to a pair of boots" is from 1871. Derogatory meaning "black person" is from 1908. Phrase to take a shine to "fancy" is American English slang from 1839. Shiner for "black eye" first recorded 1904.