shimmer v.

Middle English shinen, from Old English scinan "shed, send forth, or give out light; be radiant, be resplendent, illuminate," of persons, "be conspicuous" (class I strong verb; past tense scan, past participle scinen). This is reconstructed to be from Proto-Germanic *skeinanan (source also of Old Saxon and Old High German skinan, Old Norse and Old Frisian skina, Dutch schijnen, German scheinen, Gothic skeinan "to shine, appear"), which perhaps is from a PIE root *skai- "to shine, to gleam" (source also of Old Church Slavonic sinati "to flash up, shine").

Of smoothed or polished surfaces, "gleam, give off reflected light," late Old English. Of a person, a face, "be fair-skinned, be beautiful," c. 1200. Also used in Middle English of night when cloudless and starlit. The transitive sense of "cause to shine" is from 1580s; the meaning "to black (boots)" is from 1610s. Related: Shined (in the shoe polish sense), otherwise shone; shining.

Germanic derivational suffix of verbs, indicating repeated or diminutive action, as in clamber, clatter, flicker (v.), glitter (v.), quaver, shimmer, slumber (v.), wander, waver. Compare also snaker (Middle English snakeren) "to sneak, slink" (c. 1200), from Old Norse.