blink (n.) Look up blink at Dictionary.com
1590s, "a glance;" see blink (v.). As is the case with the verb, there is a similar word in Middle English, in use from c. 1300, that might represent a native form of the same root.
blink (v.) Look up blink at Dictionary.com
1580s, perhaps from Middle Dutch blinken "to glitter," which is of uncertain origin, possibly, with German blinken "to gleam, sparkle, twinkle," from a nasalized form of base found in Old English blican "to shine, glitter" (from PIE root *bhel- (1) "to shine, flash, burn").

Middle English had blynke (c. 1300) in the sense "a brief gleam or spark," perhaps a variant of blench "to move suddenly or sharply; to raise one's eyelids" (c. 1200), perhaps from the rare Old English blencan "deceive." Related: Blinked; blinking. The last, as a euphemism for a stronger word, is attested by 1914.