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]
(..) Sure they would Baby, I've done... You see, this is a moral test of oneself. Whether or not you can maintain loyalty. Because being loyal is very important. They never get tired of puttin' me down And I never know (..)1994 Pulp Fiction