The Collaborative International Dictionary of English v.0.48:
Blench \Blench\, v. i. [imp. & p. p. Blenched; p. pr. & vb. n.
Blenching.] [OE. blenchen to blench, elude, deceive, AS.
blencan to deceive; akin to Icel. blekkja to impose upon.
Prop. a causative of blink to make to wink, to deceive. See
Blink, and cf. 3d Blanch.]
1. To shrink; to start back; to draw back, from lack of
courage or resolution; to flinch; to quail.
Blench not at thy chosen lot. --Bryant.
This painful, heroic task he undertook, and never
blenched from its fulfillment. --Jeffrey.
2. To fly off; to turn aside. [Obs.]
Though sometimes you do blench from this to that.