barb

noun

1
one of the parallel filaments projecting from the main shaft of a feather
2
a subsidiary point facing opposite from the main point that makes an arrowhead or spear hard to remove
3
the pointed part of barbed wire
4
an aggressive remark directed at a person like a missile and intended to have a telling effect
his parting shot was `drop dead'
she threw shafts of sarcasm

Also useful for “barb”:Unscrambler— Turn loose letters into real words