The story
Blend of 4chan + Tumblr. Originated in 2010 after 4chan's /b/ board "declared war" on the Tumblr community.
Etymology from Wiktionary, CC BY-SA 4.0.
4chumblr
Today it means: A ship, or fictional romantic relationship, of Tumblr and 4chan (respectively personified as a woman with blue hair and a faceless green man). Full definition →