Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings

to know; to recognize; to be able to distinguish

Current objective situation, trend of the times, or pressing matters of the day (often used in the phrase 识时务者为俊杰 shí​shí​wù​zhě​wéi​jùn​jié)