He 'kept/maintained his cool' [=he didn't get angry or upset] even though it was clear that he was being unfairly treated.
He was struggling to 'maintain his cool/composure'. [=he was struggling not to become angry or upset]
They barely had enough food to 'maintain life'. [=to make it possible for life to exist or continue]
(..) I'll do it myself. What's the big surprise? Oh. Curtain. Yeah. I put this in so we can maintain our separate zones. What if I want to come see my stuff? That's the best part. It's all back in your closet. So, cool. (..)2010 TvShow: Scrubs Title: Our Thanks Season: 9 Episode 13