The word "unguarded" means not protected, not cautious or not carefully watched out for. It describes a situation where someone or something is vulnerable or exposed to possible harm or danger. Full definition
On calls he can not monitor personally, Mr. Kelly or a deputy will usually double - back to debrief the caller on any promises the president may have made in unguarded moments. (nytimes.com)
It is in unguarded moments such as these that we see what the green mindset is really made of. (climate-resistance.org)
Following the release of unguarded comments by Jon Lansman about his plans to do a deal with Unite to secure Corbyn's legacy Tom Watson has gone on the offensive. (totalpolitics.com)