Crass means rude and unfeeling in a thick-skinned, tasteless way. Not merely wrong — insensitive with it.
It attaches to remarks, commercialism and stupidity, and crass insensitivity is close to a fixed phrase. What separates it from merely rude is the obliviousness, since a crass comment is made by somebody who has not noticed what the moment required. The word once simply meant thick or dense, which is exactly the image still underneath it. Tactless and vulgar cover neighbouring ground.
1adjectivecrassStupidly insensitive and lacking in taste.
“It was a crass thing to say at a funeral.”
Also accepted in games: tactless, vulgar
Latin
crassus — dense, thick, gross, fat, heavy
Old French
cras
Middle English
cras
English, today
crass
From Middle English cras, craas, from Old French cras, from Latin crassus (“dense, thick, gross, fat, heavy”). a doublet of grease.
Etymology from Wiktionary, CC BY-SA