The phrase "put up bluff" means to pretend to be confident or knowledgeable about something when in fact you are not. Synonyms for this phrase include "bluff," "pose," "feign," "simulate," "fake," and "assume." Other words that can be used in place of "put up bluff" are "fake it," "act as if," "pretend," and "play the part." These synonyms convey the same idea of someone projecting an image of confidence or expertise in a particular area, even if they have little to no actual knowledge or experience in that field. Regardless of which synonym is used, the underlying meaning remains the same.