态 (tài) means "state," "condition," or "attitude." It commonly appears as a component in compound words such as 态度 (attitude), 状态 (state/condition), and 生态 (ecology). On its own, it conveys the idea of a manner or form of being.
他今天的状态不太好,看起来很疲惫。
Tā jīntiān de zhuàngtài bù tài hǎo, kàn qǐlái hěn píbèi.
He's not in great shape today; he looks very tired.
我们要以积极的心态面对生活中的困难。
Wǒmen yào yǐ jījí de xīntài miànduì shēnghuó zhōng de kùnnán.
We should face life's difficulties with a positive attitude.
这个城市的生态环境保护得非常好。
Zhège chéngshì de shēngtài huánjìng bǎohù de fēicháng hǎo.
This city's ecological environment is very well protected.