“Hold on. Just hear me out first.”
You are at a meeting for the homeowners' association for your neighborhood. You have made a suggestion to raise the homeowner's fee, but the other members immediately started making noises and complaining before you could explain your reasons for raising it. You want everyone to listen to your reasons first before deciding, so you say this.
Hold on. Just hear me out first.
This means "Wait" — especially when someone doesn't seem to want to wait:
Hold on. Wait for me!
This phrase can sound bossy, so you might add something to the end to make it sound softer:
Hold on for just a second.
This phrase means to listen to someone's complete explanation before making a conclusion about something. If you think that someone isn't listening to your explanation, you can ask them to "hear you out":
Hey, listen. Hear me out. It wasn't my fault!
And you can describe the situation like this:
She wouldn't even hear me out.