The phrase "gave lowdown" means to provide information or details about something. Antonyms of this phrase could include terms such as "kept quiet," "withheld information," "masked the truth," or "concealed the facts." These antonyms suggest a lack of transparency or communication, as opposed to being forthright and honest about a given situation. Additionally, antonyms of "gave lowdown" may suggest a level of ambiguity or uncertainty about what is being discussed or communicated. Overall, antonyms of this phrase can be associated with secrecy, deception, and lack of clarity, whereas "gave lowdown" conveys a sense of openness and straightforwardness.