be (one's)/the main squeeze

slang

1. To be one's romantic partner. Who's your main squeeze these days? Someone new? Leia is his main squeeze—they've been dating for a few months now. He has a new main squeeze already? Darn, I really wanted to ask him out!

2. To be the most important person in a particular area. Stewart just got promoted, so he's now the main squeeze in our department. I don't care what your supervisor said. I'm the boss here—the main squeeze, if you will. I make the rules. The headmaster is the main squeeze, so you'll have to get all of this approved by her.