noun
addiction; being hooked on; being absorbed in
Describes a strong habit or obsession, often with a nuance of being unable to stop. Commonly used in the phrase 病みつきになる (to become addicted/hooked).
このゲームは本当に病みつきになる。
This game is really addictive.
彼はギャンブルが病みつきになって、大変なことになった。
He got hooked on gambling and ended up in serious trouble.
noun
falling ill; becoming sick
Literally 'becoming ill.' This sense is less common in modern Japanese and is often replaced by 病気になる. It may appear in older or literary contexts.
病みつきになってから、彼はめっきり痩せてしまった。
After falling ill, he became noticeably thin.
Compound of 病み (yami, the continuative form of 病む 'to be ill') + つき (tsuki, the continuative form of 付く 'to attach'). Literally 'illness-attaching,' it originally referred to falling ill, and later extended to the idea of being 'afflicted' with a habit or addiction.