blot = blemish, black + spot, plot, dot; there is also an obsolete splot.
blunt = blind + stunt.
crouch = cringe, crook, crawl, †crouk + couch.
flush = flash + blush.
frush = frog + thrush (all three names of the same disease in a horse’s foot).
glaze (Shakespeare) = glare + gaze.
good-bye = good-night, good-morning + godbye (God be with ye).
knoll = knell + toll.
scroll = scrow + roll.
slash = slay, sling, slat + gash, dash.