Almost never appears alone in modern Chinese. You'll meet it in two contexts: the reduplicated 孜孜 (diligently, as in 孜孜不倦) and the loanword 孜然 (cumin).
memory
Mnemonic: 子 (child) under 攴 (a hand striking) — a child being prodded to keep working. The character literally pictures someone being kept at it.
