shimmer
n.
"a tremulous light," 1821, from shimmer, v..
v.
Old English scimerian "to glitter, shimmer, glisten, shine," related to (perhaps a frequentative of) scimian "to shine," from Proto-Germanic *skim- (cognates: Swedish skimra, Dutch schemeren "to glitter," German schimmern), from PIE root *skai- "to gleam, to shine" (see shine, v.. Related: Shimmered; shimmering.