The phrase "uncomfortable silence" means a period of quiet when people feel awkward or uneasy because they don't know what to say or how to fill the silence. Full definition
Several seconds of uncomfortable silence constituted the only response to this question, and then the chairman moved on to the next raised hand, the next issue. (religion-online.org)
When you do eventually meet up you will already know information about them, giving you something to talk about, therefore avoiding those moments of uncomfortable silence. (datingtolove.com)
But, pressing the issue, Colbert brought the conversation back to the complaints against him, leaving the Ed Sullivan Theater in uncomfortable silence as the fidgeting Franco alternated between stating that Tuesday's allegations were «not accurate» and making vague allusions to needing to «change [his] perspective where it's off.» (avclub.com)