not say/hear a dicky bird
not hear a dicky bird
To not hear or receive any sound, utterance, or item of communication. ("Dicky bird" is sometimes hyphenated.) We haven't heard a dicky-bird out of the kids all night—I think one of us should go check on them.
not say a dicky bird
To not say or communicate anything at all. ("Dicky bird" is sometimes hyphenated.) We've had him detained for four hours, but he won't say a dicky bird to us about his involvement in the robbery.