Morale is the spirit a group has that makes them want to succeed. It's a sense of well-being that comes from confidence, usefulness, and purpose.
We often talk about the morale of groups in tough situations, and we can describe them as having "good morale" or "low morale." If too many members of a combat unit are killed and the surviving soldiers start to doubt they’ll make it home alive, then their morale is very very low. We can also talk about individual morale. In order to succeed, a sailor on a solo trip around the world needs plenty of ways to keep her morale up.