There are various synonyms for the phrase "private opinions". One such word is "personal views", which indicates individual beliefs and attitudes that are not necessarily shared by others. "Subjective judgments" is another substitute, which refers to the personal opinions formed based on one's own experiences, feelings, and perspectives. "Unshared thoughts" is a phrase that suggests ideas that one keeps to oneself, not wanting to share them with others. "Internal reflections" can also be used to describe private opinions, implying a process of contemplation and introspection that leads to individual conclusions. Overall, there are numerous synonyms for the phrase "private opinions" that can be used depending on the context and intent of the message.