obscurity可数吗

obscurity n.
1 [U]the state in which sb/sth is not well known or has been forgotten默默无闻；无名
2 [U,C,usually pl.]the quality of being difficult to understand; something that is difficult to understand费解；晦涩；难懂的事
3 [U](literary)darkness黑暗

第一个和第三个意都不可数，第二个意即可数又不可数，可数时常用单数