(switched) off — indicates that a device, function, or setting is turned off or not operating.
テレビの電源をオフにして寝た。
I turned the TV off and went to bed.
通知をオフにしておかないと、夜中も音が鳴るよ。
If you don't turn notifications off, they'll sound even during the night.
設定画面でBluetoothをオフにする。
Turn Bluetooth off in the settings screen.
off-season — the period when an activity (sport, tourism, business) is not in its peak season.
冬はスキー場のオフだから、宿泊料金が安い。
Winter is the off-season for that ski resort, so lodging is cheap.
チームは今オフに新しい選手を補強する予定だ。
The team plans to recruit new players during the off-season.
offset — abbreviation for offset (e.g., printing offset, or an offset amount); used in technical contexts.
このポスターはオフ印刷で仕上げる予定だ。
This poster will be finished using offset printing.
会計上、いくつかのコストをオフで処理した。
In accounting, some costs were processed as offsets.
off-road — shorthand for off-road driving/terrain; refers to unpaved roads or driving outside paved surfaces.
週末は友達とオフ車でオフを走りに行く。
This weekend I'm going off-road with friends on off-road bikes.
オフ仕様のタイヤに交換した方がいいよ。
You should change to off-road-spec tires.
offline — not connected to the internet or a network; the state of being disconnected.
飛行機モードにしていると端末はオフになる（オフライン状態）。
If you put your phone in airplane mode, the device goes off (offline).
資料をオフで読むためにダウンロードしておいた。
I downloaded the materials so I could read them offline.
サーバーが落ちている間、サービスはオフだった。
While the server was down, the service was offline.
an offline get-together — used in slang to refer to meeting in person people who met online (as in 'off-kai').
SNSで知り合った人たちとオフで会うことになった。
I arranged to meet in person (offline) with people I met on social media.
来週のオフ会には初めて参加する予定だ。
I plan to attend the offline meetup next week for the first time.
offside — abbreviation used in sports (e.g., soccer) to indicate an offside infraction or position.
審判はオフを取ったが、リプレイでは微妙だった。
The referee called an offside, but the replay showed it was marginal.
彼のゴールはオフのため取り消された。
His goal was disallowed for offside.
a day off — colloquial use meaning a day without work or scheduled obligations.
明日はオフだから、家でゆっくりするつもりだ。
Tomorrow is my day off, so I plan to relax at home.
シフトを調整して週末をオフにしてもらった。
I adjusted my shift so I could have the weekend off.
連休のオフを利用して旅行に行った。
I used my days off during the long holiday to travel.
off (as a suffix) — indicating a discount or reduction from a price or amount (e.g., 20% off).
このジャケットは今セールで30％オフだ。
This jacket is 30% off in the sale right now.
会員はさらに10%オフになります。
Members get an additional 10% off.
二点買うと合計から500円オフになるキャンペーン中だ。
There's a campaign: buy two items and get 500 yen off the total.
low- / reduced — used on food/product labels to indicate lower or reduced content (e.g., low-sugar, low-calorie).
これは糖質オフの商品なので、ダイエット中の人に人気だ。
This is a low-sugar product, so it's popular with people on diets.
カロリーオフ表示の飲料を選んだ。
I chose a drink labeled as low-calorie.
このヨーグルトは脂肪分オフでさっぱりしている。
This yogurt is reduced-fat and tastes light.