Is it farther or further?
early 14c., "to hurt, damage," from Old French blemiss- "to turn pale," extended stem of blemir, blesmir "to make pale; stain, discolor," also "to injure" (13c., Modern French blêmir), probably from Frankish *blesmjan "to cause to turn pale," or some other Germanic source, from Proto-Germanic *blas "shining, white," from PIE root *bhel- (1) "to shine, flash, burn" (see bleach (v.)).
The order of appearance of senses in Middle English is "hurt, damage;" "impair morally, sully" (late 14c.); "mar, spoil, injure" (early 15c.); "to mar the beauty or soundness of" (mid-15c.). Related: Blemished; blemishing.
1520s, from blemish (v.).
blemish blem·ish (blěm'ĭsh)
A small circumscribed alteration of the skin considered to be unesthetic but insignificant.
imperfection or bodily deformity excluding men from the priesthood, and rendering animals unfit to be offered in sacrifice (Lev. 21:17-23; 22:19-25). The Christian church, as justified in Christ, is "without blemish" (Eph. 5:27). Christ offered himself a sacrifice "without blemish," acceptable to God (1 Pet. 1:19).