The phrase "gave the lowdown" means to provide information or details about a particular topic. Some antonyms for this phrase could include "kept mum," "withheld information," "concealed details," or "kept quiet." These words all convey a sense of secrecy or a reluctance to share information. Other antonyms could include phrases like "skimmed over the surface," "provided incomplete information," or "glossed over details." These phrases suggest a lack of depth or thoroughness in the information provided. When looking for antonyms for "gave the lowdown," it is helpful to think about words and phrases that suggest the opposite of clarity, forthrightness, or completeness.