Canker @ a gangrene or mortification which gradually spreads over the whole body ( 2Timothy:2:17). In James:5:3 "cankered" means "rusted" (R.V.) or tarnished.
Cankerworm @ (Heb. yelek), "the licking locust," which licks up the grass of the field; probably the locust at a certain stage of its growth, just as it emerges from the caterpillar state Joel:1:4Joel:2:25). The word is rendered "caterpillar" in Psalms:105:34; Jeremiah:51:14Jeremiah:51:17 (but R.V. "canker-worm"). "It spoileth and fleeth away" Nahum:3:16), or as some read the passage, "The cankerworm putteth off [i.e., the envelope of its wings], and fleeth away."