To utter or tell unnecessarily, or in a thoughtless manner; to publish (secrets or trifles) without reserve or discretion
If someone blabs about something secret, they tell people about it. Her mistake was to blab about their affair No blabbing to your mates! She'll blab it all over the school. to tell someone something that should be kept secret blab to (blab (14-20 centuries), probably from the sound)