One of the nine descriptors of morality for intelligent creatures: lawful good (LG), neutral good (NG), chaotic good (CG), lawful neutral (LN), neutral (N), chaotic neutral (CN), lawful evil (LE), neutral evil (NE), and chaotic evil (CE).
In a monster entry, the alignment line gives the alignment that the creature is most likely to have. Every entry includes a qualifier that indicates how broadly that alignment applies to all monsters of that kind.
Always: The creature is born with the indicated alignment. The creature may have a hereditary predisposition to the alignment or come from a plane that predetermines it. It is possible for individuals to change alignment, but such individuals are either unique or rare exceptions.
Usually: The majority (more than 50%) of these creatures have the given alignment. This may be due to strong cultural influences, or it may be a legacy of the creatures' origin. For example, most elves inherited their chaotic good alignment from their creator, the deity Corellon Larethian.
Often: The creature tends toward the given alignment, either by nature or nurture, but not strongly. A plurality (40-50%) of individuals have the given alignment, but exceptions are common.