late 14c., blober "a bubble, bubbling water; foaming waves," probably echoic of bubbling water. Original notion of "bubbling, foaming" survives in the figurative verbal meaning "to weep, cry" (c.1400). Meaning "whale fat" first attested 1660s; earlier it was used in reference to jellyfish (c.1600) and of whale oil (mid-15c.). As an adjective from 1660s.

late 14c., "to seethe, bubble," from blubber, n.. Meaning "to cry, to overflow with weeping" is from c.1400. Related: Blubbered; blubbering.