/blab/ , v. , blabbed, blabbing , n. Informal.
v.t.
1. to reveal indiscreetly and thoughtlessly: They blabbed my confidences to everyone.
v.i.
2. to talk or chatter indiscreetly or thoughtlessly: Don't confide in him, because he blabs. She blabbed so much I couldn't hear the concert.
n.
3. idle, indiscreet chattering.
4. a person who blabs; blabbermouth.
Also, blabber /blab"euhr/ .
[ 1325-75; ME blabbe (n.), perh. back formation from blaberen to blabber; c. ON blabbra, G plappern ]