Antonyms for the phrase "ample amount" refer to different types of scarcity or insufficiency. For instance, the opposite of an ample amount is a "meager" or "inadequate" amount. These antonyms suggest a lack of necessary resources, whether that refers to money, time, or something else. Another antonym is "scanty," meaning there is barely enough of something to meet one's needs. Other antonyms include "scarce," "insufficient," "sparse," or "wanting." These words convey a sense of difficulty, challenge or inconvenience when dealing with a shortage, and a need to find a solution or alternative option.