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]
(..) Now, for instance, if you just have a regular old raggedy bourbon drunk, you know, they go like: You know, and they're really trying to maintain. And the people keep leaning the room on them, you know. See. Now you can get a gin drunk. Gin and vodka, you know, martinis, now, these are the people, (..)1983 Bill Cosby: Himself