此事 (cǐ shì) means “this matter”. It is an HSK 6 Chinese word in the HSK 3.0 vocabulary.
Practice each character:
此事关系重大,不可大意。
Cǐ shì guānxì zhòngdà, bùkě dàyì.
This matter is of great importance; don't be careless.
Updated: 2026-07-18