shimmer: [OE] Shimmer goes back to a prehistoric Germanic *skim- (source also of German schimmern ‘glitter, gleam’). This was an extension of the base *ski-, from which English gets sheer and shine. => sheer, shine
shimmer (n.)
"a tremulous light," 1821, from shimmer (v.).
shimmer (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.