Blab, v. i.
To talk thoughtlessly or without discretion; to tattle; to tell tales. She must burst or blab. Dryden.
2 other Webster entries under this spelling
Blab, v. t. [imp. & p. p. Blabbed (p. pr. & vb. n. Blabbing.]
To utter or tell unnecessarily, or in a thoughtless manner; to publish (secrets or trifles) without reserve or discretion. Udall. And yonder a vile physician blabbing The case of his patient. Tennyson.
Blab, n.
One who blabs; a babbler; a telltale. "Avoided as a blab." Milton. For who will open himself to a blab or a babbler. Bacon.