1To enclose, surround, or encircle something (for example with a fence or wall).
庭を塀で囲って犬が逃げないようにした。
I fenced in the garden so the dog can't escape.
美術館は展示をロープで囲って説明を書いてある。
The museum roped off the exhibits and put up descriptions.
畑をネットで囲えば害獣の被害を減らせる。
If you surround the field with netting, you can reduce damage from animals.
2To shelter, shield, hide, or protect someone or something (e.g., shelter a criminal or shield someone from harm).
彼は問題の証拠を隠すために家族を囲っていたと疑われた。
He was suspected of sheltering his family to hide evidence of the problem.
親は子供を悪い影響から囲うように守った。
Parents protected their children as if surrounding them from bad influences.
彼女は都会の騒音から自分の部屋を囲うように窓を二重にした。
She surrounded her room with double windows to shield it from city noise.
3To keep someone (e.g., a mistress) privately in one's care — to keep or maintain a secret relationship.
彼は長年、複数の女性を囲っていたと週刊誌が報じた。
A weekly magazine reported that he had kept several women privately for many years.
そんな関係を公にせずに囲うのは不誠実だ。
Keeping such a relationship secret and private is dishonest.
芸能人が若い女性を囲うという噂が出た。
There were rumors that a celebrity was keeping a young woman privately.
4To store or preserve (vegetables, fruit, etc.) for later use.
冬に備えて野菜を塩漬けにして囲っておいた。
I salted and preserved vegetables in preparation for winter.
古い家では食料を囲って地下に保管した例がある。
In old houses there are examples of storing food in underground enclosures.
漁村では魚を塩や氷で囲って保存する方法が利用されている。
In fishing villages, methods of preserving fish with salt or ice are used.
5Archaic usage meaning 'to protect' or 'to shelter'; now archaic or literary.
古い史書には『城を囲う』と書かれており、領民を守る意が込められている（古語）。
Old chronicles use phrases like 'to kaku(u) the castle', implying protection of the people (archaic).