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 think human nature is the enemy. It's human nature to keep secrets, lie, steal. And I wanna eradicate that. That's how we'll maintain a stable, peaceful society. You would help me with that, wouldn't you? How would I help you? You're aware that Abnegation is undermining (..)2014 Divergent