"Not really" is a commonly used phrase in English and can be replaced with many other words or phrases that convey a similar meaning. Some of the synonyms for "not really" include "not exactly," "not precisely," "not particularly," "not truly," "not completely," "not entirely," "not wholly," "not fully," "not totally," "not genuinely" and "not authentically." Using different synonyms for "not really" can add variety to one's writing or speech and convey a more specific or nuanced meaning. It is always important to choose the right synonym that fits the context and tone of the conversation or writing.