1To be moderate in something; to refrain from excess — to limit or moderate one's actions (often used for consumption or behavior).
健康診断の結果が悪かったので、医者の勧めで脂っこいものを差し控えている。
Because my health check results were bad, I'm refraining from fatty foods on my doctor's advice.
会議の日はアルコールを差し控えておくつもりだ。
I intend to avoid alcohol on the day of the meeting.
重要な手術の前なので、激しい運動は差し控えたほうがいい。
Since it's before an important operation, it's better to refrain from strenuous exercise.
2To refrain from doing something (usually saying or announcing); to withhold an announcement or comment — often used in formal or official contexts.
調査中につき詳細については差し控えますが、関係機関と連携しています。
While the investigation is ongoing, I must refrain from giving details, but we are coordinating with the relevant agencies.
個人情報に関する質問には差し控えさせていただきます。
I will refrain from answering questions about personal information.
3(Rare) Used intransitively to mean 'to be nearby' or 'to stand in reserve' — a literary/formal usage meaning to remain close at hand or wait nearby.
式典の間、警備員が入口に差し控えていた。
During the ceremony, security guards stood by at the entrance.